SemaOverload.cpp revision 52ae30c90106ce7086e0787e95dd6536079202e4
1//===--- SemaOverload.cpp - C++ Overloading ---------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file provides Sema routines for C++ overloading. 11// 12//===----------------------------------------------------------------------===// 13 14#include "Sema.h" 15#include "SemaInherit.h" 16#include "clang/Basic/Diagnostic.h" 17#include "clang/Lex/Preprocessor.h" 18#include "clang/AST/ASTContext.h" 19#include "clang/AST/Expr.h" 20#include "clang/AST/ExprCXX.h" 21#include "clang/AST/TypeOrdering.h" 22#include "llvm/ADT/SmallPtrSet.h" 23#include "llvm/ADT/STLExtras.h" 24#include "llvm/Support/Compiler.h" 25#include <algorithm> 26 27namespace clang { 28 29/// GetConversionCategory - Retrieve the implicit conversion 30/// category corresponding to the given implicit conversion kind. 31ImplicitConversionCategory 32GetConversionCategory(ImplicitConversionKind Kind) { 33 static const ImplicitConversionCategory 34 Category[(int)ICK_Num_Conversion_Kinds] = { 35 ICC_Identity, 36 ICC_Lvalue_Transformation, 37 ICC_Lvalue_Transformation, 38 ICC_Lvalue_Transformation, 39 ICC_Qualification_Adjustment, 40 ICC_Promotion, 41 ICC_Promotion, 42 ICC_Conversion, 43 ICC_Conversion, 44 ICC_Conversion, 45 ICC_Conversion, 46 ICC_Conversion, 47 ICC_Conversion, 48 ICC_Conversion 49 }; 50 return Category[(int)Kind]; 51} 52 53/// GetConversionRank - Retrieve the implicit conversion rank 54/// corresponding to the given implicit conversion kind. 55ImplicitConversionRank GetConversionRank(ImplicitConversionKind Kind) { 56 static const ImplicitConversionRank 57 Rank[(int)ICK_Num_Conversion_Kinds] = { 58 ICR_Exact_Match, 59 ICR_Exact_Match, 60 ICR_Exact_Match, 61 ICR_Exact_Match, 62 ICR_Exact_Match, 63 ICR_Promotion, 64 ICR_Promotion, 65 ICR_Conversion, 66 ICR_Conversion, 67 ICR_Conversion, 68 ICR_Conversion, 69 ICR_Conversion, 70 ICR_Conversion, 71 ICR_Conversion 72 }; 73 return Rank[(int)Kind]; 74} 75 76/// GetImplicitConversionName - Return the name of this kind of 77/// implicit conversion. 78const char* GetImplicitConversionName(ImplicitConversionKind Kind) { 79 static const char* Name[(int)ICK_Num_Conversion_Kinds] = { 80 "No conversion", 81 "Lvalue-to-rvalue", 82 "Array-to-pointer", 83 "Function-to-pointer", 84 "Qualification", 85 "Integral promotion", 86 "Floating point promotion", 87 "Integral conversion", 88 "Floating conversion", 89 "Floating-integral conversion", 90 "Pointer conversion", 91 "Pointer-to-member conversion", 92 "Boolean conversion", 93 "Derived-to-base conversion" 94 }; 95 return Name[Kind]; 96} 97 98/// StandardConversionSequence - Set the standard conversion 99/// sequence to the identity conversion. 100void StandardConversionSequence::setAsIdentityConversion() { 101 First = ICK_Identity; 102 Second = ICK_Identity; 103 Third = ICK_Identity; 104 Deprecated = false; 105 ReferenceBinding = false; 106 DirectBinding = false; 107 CopyConstructor = 0; 108} 109 110/// getRank - Retrieve the rank of this standard conversion sequence 111/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the 112/// implicit conversions. 113ImplicitConversionRank StandardConversionSequence::getRank() const { 114 ImplicitConversionRank Rank = ICR_Exact_Match; 115 if (GetConversionRank(First) > Rank) 116 Rank = GetConversionRank(First); 117 if (GetConversionRank(Second) > Rank) 118 Rank = GetConversionRank(Second); 119 if (GetConversionRank(Third) > Rank) 120 Rank = GetConversionRank(Third); 121 return Rank; 122} 123 124/// isPointerConversionToBool - Determines whether this conversion is 125/// a conversion of a pointer or pointer-to-member to bool. This is 126/// used as part of the ranking of standard conversion sequences 127/// (C++ 13.3.3.2p4). 128bool StandardConversionSequence::isPointerConversionToBool() const 129{ 130 QualType FromType = QualType::getFromOpaquePtr(FromTypePtr); 131 QualType ToType = QualType::getFromOpaquePtr(ToTypePtr); 132 133 // Note that FromType has not necessarily been transformed by the 134 // array-to-pointer or function-to-pointer implicit conversions, so 135 // check for their presence as well as checking whether FromType is 136 // a pointer. 137 if (ToType->isBooleanType() && 138 (FromType->isPointerType() || FromType->isBlockPointerType() || 139 First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer)) 140 return true; 141 142 return false; 143} 144 145/// isPointerConversionToVoidPointer - Determines whether this 146/// conversion is a conversion of a pointer to a void pointer. This is 147/// used as part of the ranking of standard conversion sequences (C++ 148/// 13.3.3.2p4). 149bool 150StandardConversionSequence:: 151isPointerConversionToVoidPointer(ASTContext& Context) const 152{ 153 QualType FromType = QualType::getFromOpaquePtr(FromTypePtr); 154 QualType ToType = QualType::getFromOpaquePtr(ToTypePtr); 155 156 // Note that FromType has not necessarily been transformed by the 157 // array-to-pointer implicit conversion, so check for its presence 158 // and redo the conversion to get a pointer. 159 if (First == ICK_Array_To_Pointer) 160 FromType = Context.getArrayDecayedType(FromType); 161 162 if (Second == ICK_Pointer_Conversion) 163 if (const PointerType* ToPtrType = ToType->getAsPointerType()) 164 return ToPtrType->getPointeeType()->isVoidType(); 165 166 return false; 167} 168 169/// DebugPrint - Print this standard conversion sequence to standard 170/// error. Useful for debugging overloading issues. 171void StandardConversionSequence::DebugPrint() const { 172 bool PrintedSomething = false; 173 if (First != ICK_Identity) { 174 fprintf(stderr, "%s", GetImplicitConversionName(First)); 175 PrintedSomething = true; 176 } 177 178 if (Second != ICK_Identity) { 179 if (PrintedSomething) { 180 fprintf(stderr, " -> "); 181 } 182 fprintf(stderr, "%s", GetImplicitConversionName(Second)); 183 184 if (CopyConstructor) { 185 fprintf(stderr, " (by copy constructor)"); 186 } else if (DirectBinding) { 187 fprintf(stderr, " (direct reference binding)"); 188 } else if (ReferenceBinding) { 189 fprintf(stderr, " (reference binding)"); 190 } 191 PrintedSomething = true; 192 } 193 194 if (Third != ICK_Identity) { 195 if (PrintedSomething) { 196 fprintf(stderr, " -> "); 197 } 198 fprintf(stderr, "%s", GetImplicitConversionName(Third)); 199 PrintedSomething = true; 200 } 201 202 if (!PrintedSomething) { 203 fprintf(stderr, "No conversions required"); 204 } 205} 206 207/// DebugPrint - Print this user-defined conversion sequence to standard 208/// error. Useful for debugging overloading issues. 209void UserDefinedConversionSequence::DebugPrint() const { 210 if (Before.First || Before.Second || Before.Third) { 211 Before.DebugPrint(); 212 fprintf(stderr, " -> "); 213 } 214 fprintf(stderr, "'%s'", ConversionFunction->getNameAsString().c_str()); 215 if (After.First || After.Second || After.Third) { 216 fprintf(stderr, " -> "); 217 After.DebugPrint(); 218 } 219} 220 221/// DebugPrint - Print this implicit conversion sequence to standard 222/// error. Useful for debugging overloading issues. 223void ImplicitConversionSequence::DebugPrint() const { 224 switch (ConversionKind) { 225 case StandardConversion: 226 fprintf(stderr, "Standard conversion: "); 227 Standard.DebugPrint(); 228 break; 229 case UserDefinedConversion: 230 fprintf(stderr, "User-defined conversion: "); 231 UserDefined.DebugPrint(); 232 break; 233 case EllipsisConversion: 234 fprintf(stderr, "Ellipsis conversion"); 235 break; 236 case BadConversion: 237 fprintf(stderr, "Bad conversion"); 238 break; 239 } 240 241 fprintf(stderr, "\n"); 242} 243 244// IsOverload - Determine whether the given New declaration is an 245// overload of the Old declaration. This routine returns false if New 246// and Old cannot be overloaded, e.g., if they are functions with the 247// same signature (C++ 1.3.10) or if the Old declaration isn't a 248// function (or overload set). When it does return false and Old is an 249// OverloadedFunctionDecl, MatchedDecl will be set to point to the 250// FunctionDecl that New cannot be overloaded with. 251// 252// Example: Given the following input: 253// 254// void f(int, float); // #1 255// void f(int, int); // #2 256// int f(int, int); // #3 257// 258// When we process #1, there is no previous declaration of "f", 259// so IsOverload will not be used. 260// 261// When we process #2, Old is a FunctionDecl for #1. By comparing the 262// parameter types, we see that #1 and #2 are overloaded (since they 263// have different signatures), so this routine returns false; 264// MatchedDecl is unchanged. 265// 266// When we process #3, Old is an OverloadedFunctionDecl containing #1 267// and #2. We compare the signatures of #3 to #1 (they're overloaded, 268// so we do nothing) and then #3 to #2. Since the signatures of #3 and 269// #2 are identical (return types of functions are not part of the 270// signature), IsOverload returns false and MatchedDecl will be set to 271// point to the FunctionDecl for #2. 272bool 273Sema::IsOverload(FunctionDecl *New, Decl* OldD, 274 OverloadedFunctionDecl::function_iterator& MatchedDecl) 275{ 276 if (OverloadedFunctionDecl* Ovl = dyn_cast<OverloadedFunctionDecl>(OldD)) { 277 // Is this new function an overload of every function in the 278 // overload set? 279 OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(), 280 FuncEnd = Ovl->function_end(); 281 for (; Func != FuncEnd; ++Func) { 282 if (!IsOverload(New, *Func, MatchedDecl)) { 283 MatchedDecl = Func; 284 return false; 285 } 286 } 287 288 // This function overloads every function in the overload set. 289 return true; 290 } else if (FunctionDecl* Old = dyn_cast<FunctionDecl>(OldD)) { 291 // Is the function New an overload of the function Old? 292 QualType OldQType = Context.getCanonicalType(Old->getType()); 293 QualType NewQType = Context.getCanonicalType(New->getType()); 294 295 // Compare the signatures (C++ 1.3.10) of the two functions to 296 // determine whether they are overloads. If we find any mismatch 297 // in the signature, they are overloads. 298 299 // If either of these functions is a K&R-style function (no 300 // prototype), then we consider them to have matching signatures. 301 if (isa<FunctionTypeNoProto>(OldQType.getTypePtr()) || 302 isa<FunctionTypeNoProto>(NewQType.getTypePtr())) 303 return false; 304 305 FunctionTypeProto* OldType = cast<FunctionTypeProto>(OldQType.getTypePtr()); 306 FunctionTypeProto* NewType = cast<FunctionTypeProto>(NewQType.getTypePtr()); 307 308 // The signature of a function includes the types of its 309 // parameters (C++ 1.3.10), which includes the presence or absence 310 // of the ellipsis; see C++ DR 357). 311 if (OldQType != NewQType && 312 (OldType->getNumArgs() != NewType->getNumArgs() || 313 OldType->isVariadic() != NewType->isVariadic() || 314 !std::equal(OldType->arg_type_begin(), OldType->arg_type_end(), 315 NewType->arg_type_begin()))) 316 return true; 317 318 // If the function is a class member, its signature includes the 319 // cv-qualifiers (if any) on the function itself. 320 // 321 // As part of this, also check whether one of the member functions 322 // is static, in which case they are not overloads (C++ 323 // 13.1p2). While not part of the definition of the signature, 324 // this check is important to determine whether these functions 325 // can be overloaded. 326 CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old); 327 CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New); 328 if (OldMethod && NewMethod && 329 !OldMethod->isStatic() && !NewMethod->isStatic() && 330 OldMethod->getTypeQualifiers() != NewMethod->getTypeQualifiers()) 331 return true; 332 333 // The signatures match; this is not an overload. 334 return false; 335 } else { 336 // (C++ 13p1): 337 // Only function declarations can be overloaded; object and type 338 // declarations cannot be overloaded. 339 return false; 340 } 341} 342 343/// TryImplicitConversion - Attempt to perform an implicit conversion 344/// from the given expression (Expr) to the given type (ToType). This 345/// function returns an implicit conversion sequence that can be used 346/// to perform the initialization. Given 347/// 348/// void f(float f); 349/// void g(int i) { f(i); } 350/// 351/// this routine would produce an implicit conversion sequence to 352/// describe the initialization of f from i, which will be a standard 353/// conversion sequence containing an lvalue-to-rvalue conversion (C++ 354/// 4.1) followed by a floating-integral conversion (C++ 4.9). 355// 356/// Note that this routine only determines how the conversion can be 357/// performed; it does not actually perform the conversion. As such, 358/// it will not produce any diagnostics if no conversion is available, 359/// but will instead return an implicit conversion sequence of kind 360/// "BadConversion". 361/// 362/// If @p SuppressUserConversions, then user-defined conversions are 363/// not permitted. 364/// If @p AllowExplicit, then explicit user-defined conversions are 365/// permitted. 366ImplicitConversionSequence 367Sema::TryImplicitConversion(Expr* From, QualType ToType, 368 bool SuppressUserConversions, 369 bool AllowExplict) 370{ 371 ImplicitConversionSequence ICS; 372 if (IsStandardConversion(From, ToType, ICS.Standard)) 373 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 374 else if (!SuppressUserConversions && 375 IsUserDefinedConversion(From, ToType, ICS.UserDefined, AllowExplict)) { 376 ICS.ConversionKind = ImplicitConversionSequence::UserDefinedConversion; 377 // C++ [over.ics.user]p4: 378 // A conversion of an expression of class type to the same class 379 // type is given Exact Match rank, and a conversion of an 380 // expression of class type to a base class of that type is 381 // given Conversion rank, in spite of the fact that a copy 382 // constructor (i.e., a user-defined conversion function) is 383 // called for those cases. 384 if (CXXConstructorDecl *Constructor 385 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) { 386 if (Constructor->isCopyConstructor(Context)) { 387 // Turn this into a "standard" conversion sequence, so that it 388 // gets ranked with standard conversion sequences. 389 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 390 ICS.Standard.setAsIdentityConversion(); 391 ICS.Standard.FromTypePtr = From->getType().getAsOpaquePtr(); 392 ICS.Standard.ToTypePtr = ToType.getAsOpaquePtr(); 393 ICS.Standard.CopyConstructor = Constructor; 394 if (IsDerivedFrom(From->getType().getUnqualifiedType(), 395 ToType.getUnqualifiedType())) 396 ICS.Standard.Second = ICK_Derived_To_Base; 397 } 398 } 399 } else 400 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 401 402 return ICS; 403} 404 405/// IsStandardConversion - Determines whether there is a standard 406/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the 407/// expression From to the type ToType. Standard conversion sequences 408/// only consider non-class types; for conversions that involve class 409/// types, use TryImplicitConversion. If a conversion exists, SCS will 410/// contain the standard conversion sequence required to perform this 411/// conversion and this routine will return true. Otherwise, this 412/// routine will return false and the value of SCS is unspecified. 413bool 414Sema::IsStandardConversion(Expr* From, QualType ToType, 415 StandardConversionSequence &SCS) 416{ 417 QualType FromType = From->getType(); 418 419 // There are no standard conversions for class types, so abort early. 420 if (FromType->isRecordType() || ToType->isRecordType()) 421 return false; 422 423 // Standard conversions (C++ [conv]) 424 SCS.setAsIdentityConversion(); 425 SCS.Deprecated = false; 426 SCS.IncompatibleObjC = false; 427 SCS.FromTypePtr = FromType.getAsOpaquePtr(); 428 SCS.CopyConstructor = 0; 429 430 // The first conversion can be an lvalue-to-rvalue conversion, 431 // array-to-pointer conversion, or function-to-pointer conversion 432 // (C++ 4p1). 433 434 // Lvalue-to-rvalue conversion (C++ 4.1): 435 // An lvalue (3.10) of a non-function, non-array type T can be 436 // converted to an rvalue. 437 Expr::isLvalueResult argIsLvalue = From->isLvalue(Context); 438 if (argIsLvalue == Expr::LV_Valid && 439 !FromType->isFunctionType() && !FromType->isArrayType() && 440 !FromType->isOverloadType()) { 441 SCS.First = ICK_Lvalue_To_Rvalue; 442 443 // If T is a non-class type, the type of the rvalue is the 444 // cv-unqualified version of T. Otherwise, the type of the rvalue 445 // is T (C++ 4.1p1). 446 FromType = FromType.getUnqualifiedType(); 447 } 448 // Array-to-pointer conversion (C++ 4.2) 449 else if (FromType->isArrayType()) { 450 SCS.First = ICK_Array_To_Pointer; 451 452 // An lvalue or rvalue of type "array of N T" or "array of unknown 453 // bound of T" can be converted to an rvalue of type "pointer to 454 // T" (C++ 4.2p1). 455 FromType = Context.getArrayDecayedType(FromType); 456 457 if (IsStringLiteralToNonConstPointerConversion(From, ToType)) { 458 // This conversion is deprecated. (C++ D.4). 459 SCS.Deprecated = true; 460 461 // For the purpose of ranking in overload resolution 462 // (13.3.3.1.1), this conversion is considered an 463 // array-to-pointer conversion followed by a qualification 464 // conversion (4.4). (C++ 4.2p2) 465 SCS.Second = ICK_Identity; 466 SCS.Third = ICK_Qualification; 467 SCS.ToTypePtr = ToType.getAsOpaquePtr(); 468 return true; 469 } 470 } 471 // Function-to-pointer conversion (C++ 4.3). 472 else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) { 473 SCS.First = ICK_Function_To_Pointer; 474 475 // An lvalue of function type T can be converted to an rvalue of 476 // type "pointer to T." The result is a pointer to the 477 // function. (C++ 4.3p1). 478 FromType = Context.getPointerType(FromType); 479 } 480 // Address of overloaded function (C++ [over.over]). 481 else if (FunctionDecl *Fn 482 = ResolveAddressOfOverloadedFunction(From, ToType, false)) { 483 SCS.First = ICK_Function_To_Pointer; 484 485 // We were able to resolve the address of the overloaded function, 486 // so we can convert to the type of that function. 487 FromType = Fn->getType(); 488 if (ToType->isReferenceType()) 489 FromType = Context.getReferenceType(FromType); 490 else 491 FromType = Context.getPointerType(FromType); 492 } 493 // We don't require any conversions for the first step. 494 else { 495 SCS.First = ICK_Identity; 496 } 497 498 // The second conversion can be an integral promotion, floating 499 // point promotion, integral conversion, floating point conversion, 500 // floating-integral conversion, pointer conversion, 501 // pointer-to-member conversion, or boolean conversion (C++ 4p1). 502 bool IncompatibleObjC = false; 503 if (Context.getCanonicalType(FromType).getUnqualifiedType() == 504 Context.getCanonicalType(ToType).getUnqualifiedType()) { 505 // The unqualified versions of the types are the same: there's no 506 // conversion to do. 507 SCS.Second = ICK_Identity; 508 } 509 // Integral promotion (C++ 4.5). 510 else if (IsIntegralPromotion(From, FromType, ToType)) { 511 SCS.Second = ICK_Integral_Promotion; 512 FromType = ToType.getUnqualifiedType(); 513 } 514 // Floating point promotion (C++ 4.6). 515 else if (IsFloatingPointPromotion(FromType, ToType)) { 516 SCS.Second = ICK_Floating_Promotion; 517 FromType = ToType.getUnqualifiedType(); 518 } 519 // Integral conversions (C++ 4.7). 520 // FIXME: isIntegralType shouldn't be true for enums in C++. 521 else if ((FromType->isIntegralType() || FromType->isEnumeralType()) && 522 (ToType->isIntegralType() && !ToType->isEnumeralType())) { 523 SCS.Second = ICK_Integral_Conversion; 524 FromType = ToType.getUnqualifiedType(); 525 } 526 // Floating point conversions (C++ 4.8). 527 else if (FromType->isFloatingType() && ToType->isFloatingType()) { 528 SCS.Second = ICK_Floating_Conversion; 529 FromType = ToType.getUnqualifiedType(); 530 } 531 // Floating-integral conversions (C++ 4.9). 532 // FIXME: isIntegralType shouldn't be true for enums in C++. 533 else if ((FromType->isFloatingType() && 534 ToType->isIntegralType() && !ToType->isBooleanType() && 535 !ToType->isEnumeralType()) || 536 ((FromType->isIntegralType() || FromType->isEnumeralType()) && 537 ToType->isFloatingType())) { 538 SCS.Second = ICK_Floating_Integral; 539 FromType = ToType.getUnqualifiedType(); 540 } 541 // Pointer conversions (C++ 4.10). 542 else if (IsPointerConversion(From, FromType, ToType, FromType, 543 IncompatibleObjC)) { 544 SCS.Second = ICK_Pointer_Conversion; 545 SCS.IncompatibleObjC = IncompatibleObjC; 546 } 547 // Pointer to member conversions (4.11). 548 else if (IsMemberPointerConversion(From, FromType, ToType, FromType)) { 549 SCS.Second = ICK_Pointer_Member; 550 } 551 // Boolean conversions (C++ 4.12). 552 else if (ToType->isBooleanType() && 553 (FromType->isArithmeticType() || 554 FromType->isEnumeralType() || 555 FromType->isPointerType() || 556 FromType->isBlockPointerType() || 557 FromType->isMemberPointerType())) { 558 SCS.Second = ICK_Boolean_Conversion; 559 FromType = Context.BoolTy; 560 } else { 561 // No second conversion required. 562 SCS.Second = ICK_Identity; 563 } 564 565 QualType CanonFrom; 566 QualType CanonTo; 567 // The third conversion can be a qualification conversion (C++ 4p1). 568 if (IsQualificationConversion(FromType, ToType)) { 569 SCS.Third = ICK_Qualification; 570 FromType = ToType; 571 CanonFrom = Context.getCanonicalType(FromType); 572 CanonTo = Context.getCanonicalType(ToType); 573 } else { 574 // No conversion required 575 SCS.Third = ICK_Identity; 576 577 // C++ [over.best.ics]p6: 578 // [...] Any difference in top-level cv-qualification is 579 // subsumed by the initialization itself and does not constitute 580 // a conversion. [...] 581 CanonFrom = Context.getCanonicalType(FromType); 582 CanonTo = Context.getCanonicalType(ToType); 583 if (CanonFrom.getUnqualifiedType() == CanonTo.getUnqualifiedType() && 584 CanonFrom.getCVRQualifiers() != CanonTo.getCVRQualifiers()) { 585 FromType = ToType; 586 CanonFrom = CanonTo; 587 } 588 } 589 590 // If we have not converted the argument type to the parameter type, 591 // this is a bad conversion sequence. 592 if (CanonFrom != CanonTo) 593 return false; 594 595 SCS.ToTypePtr = FromType.getAsOpaquePtr(); 596 return true; 597} 598 599/// IsIntegralPromotion - Determines whether the conversion from the 600/// expression From (whose potentially-adjusted type is FromType) to 601/// ToType is an integral promotion (C++ 4.5). If so, returns true and 602/// sets PromotedType to the promoted type. 603bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) 604{ 605 const BuiltinType *To = ToType->getAsBuiltinType(); 606 // All integers are built-in. 607 if (!To) { 608 return false; 609 } 610 611 // An rvalue of type char, signed char, unsigned char, short int, or 612 // unsigned short int can be converted to an rvalue of type int if 613 // int can represent all the values of the source type; otherwise, 614 // the source rvalue can be converted to an rvalue of type unsigned 615 // int (C++ 4.5p1). 616 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType()) { 617 if (// We can promote any signed, promotable integer type to an int 618 (FromType->isSignedIntegerType() || 619 // We can promote any unsigned integer type whose size is 620 // less than int to an int. 621 (!FromType->isSignedIntegerType() && 622 Context.getTypeSize(FromType) < Context.getTypeSize(ToType)))) { 623 return To->getKind() == BuiltinType::Int; 624 } 625 626 return To->getKind() == BuiltinType::UInt; 627 } 628 629 // An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2) 630 // can be converted to an rvalue of the first of the following types 631 // that can represent all the values of its underlying type: int, 632 // unsigned int, long, or unsigned long (C++ 4.5p2). 633 if ((FromType->isEnumeralType() || FromType->isWideCharType()) 634 && ToType->isIntegerType()) { 635 // Determine whether the type we're converting from is signed or 636 // unsigned. 637 bool FromIsSigned; 638 uint64_t FromSize = Context.getTypeSize(FromType); 639 if (const EnumType *FromEnumType = FromType->getAsEnumType()) { 640 QualType UnderlyingType = FromEnumType->getDecl()->getIntegerType(); 641 FromIsSigned = UnderlyingType->isSignedIntegerType(); 642 } else { 643 // FIXME: Is wchar_t signed or unsigned? We assume it's signed for now. 644 FromIsSigned = true; 645 } 646 647 // The types we'll try to promote to, in the appropriate 648 // order. Try each of these types. 649 QualType PromoteTypes[6] = { 650 Context.IntTy, Context.UnsignedIntTy, 651 Context.LongTy, Context.UnsignedLongTy , 652 Context.LongLongTy, Context.UnsignedLongLongTy 653 }; 654 for (int Idx = 0; Idx < 6; ++Idx) { 655 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]); 656 if (FromSize < ToSize || 657 (FromSize == ToSize && 658 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) { 659 // We found the type that we can promote to. If this is the 660 // type we wanted, we have a promotion. Otherwise, no 661 // promotion. 662 return Context.getCanonicalType(ToType).getUnqualifiedType() 663 == Context.getCanonicalType(PromoteTypes[Idx]).getUnqualifiedType(); 664 } 665 } 666 } 667 668 // An rvalue for an integral bit-field (9.6) can be converted to an 669 // rvalue of type int if int can represent all the values of the 670 // bit-field; otherwise, it can be converted to unsigned int if 671 // unsigned int can represent all the values of the bit-field. If 672 // the bit-field is larger yet, no integral promotion applies to 673 // it. If the bit-field has an enumerated type, it is treated as any 674 // other value of that type for promotion purposes (C++ 4.5p3). 675 if (MemberExpr *MemRef = dyn_cast<MemberExpr>(From)) { 676 using llvm::APSInt; 677 if (FieldDecl *MemberDecl = dyn_cast<FieldDecl>(MemRef->getMemberDecl())) { 678 APSInt BitWidth; 679 if (MemberDecl->isBitField() && 680 FromType->isIntegralType() && !FromType->isEnumeralType() && 681 From->isIntegerConstantExpr(BitWidth, Context)) { 682 APSInt ToSize(Context.getTypeSize(ToType)); 683 684 // Are we promoting to an int from a bitfield that fits in an int? 685 if (BitWidth < ToSize || 686 (FromType->isSignedIntegerType() && BitWidth <= ToSize)) { 687 return To->getKind() == BuiltinType::Int; 688 } 689 690 // Are we promoting to an unsigned int from an unsigned bitfield 691 // that fits into an unsigned int? 692 if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) { 693 return To->getKind() == BuiltinType::UInt; 694 } 695 696 return false; 697 } 698 } 699 } 700 701 // An rvalue of type bool can be converted to an rvalue of type int, 702 // with false becoming zero and true becoming one (C++ 4.5p4). 703 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) { 704 return true; 705 } 706 707 return false; 708} 709 710/// IsFloatingPointPromotion - Determines whether the conversion from 711/// FromType to ToType is a floating point promotion (C++ 4.6). If so, 712/// returns true and sets PromotedType to the promoted type. 713bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) 714{ 715 /// An rvalue of type float can be converted to an rvalue of type 716 /// double. (C++ 4.6p1). 717 if (const BuiltinType *FromBuiltin = FromType->getAsBuiltinType()) 718 if (const BuiltinType *ToBuiltin = ToType->getAsBuiltinType()) 719 if (FromBuiltin->getKind() == BuiltinType::Float && 720 ToBuiltin->getKind() == BuiltinType::Double) 721 return true; 722 723 return false; 724} 725 726/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from 727/// the pointer type FromPtr to a pointer to type ToPointee, with the 728/// same type qualifiers as FromPtr has on its pointee type. ToType, 729/// if non-empty, will be a pointer to ToType that may or may not have 730/// the right set of qualifiers on its pointee. 731static QualType 732BuildSimilarlyQualifiedPointerType(const PointerType *FromPtr, 733 QualType ToPointee, QualType ToType, 734 ASTContext &Context) { 735 QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType()); 736 QualType CanonToPointee = Context.getCanonicalType(ToPointee); 737 unsigned Quals = CanonFromPointee.getCVRQualifiers(); 738 739 // Exact qualifier match -> return the pointer type we're converting to. 740 if (CanonToPointee.getCVRQualifiers() == Quals) { 741 // ToType is exactly what we need. Return it. 742 if (ToType.getTypePtr()) 743 return ToType; 744 745 // Build a pointer to ToPointee. It has the right qualifiers 746 // already. 747 return Context.getPointerType(ToPointee); 748 } 749 750 // Just build a canonical type that has the right qualifiers. 751 return Context.getPointerType(CanonToPointee.getQualifiedType(Quals)); 752} 753 754/// IsPointerConversion - Determines whether the conversion of the 755/// expression From, which has the (possibly adjusted) type FromType, 756/// can be converted to the type ToType via a pointer conversion (C++ 757/// 4.10). If so, returns true and places the converted type (that 758/// might differ from ToType in its cv-qualifiers at some level) into 759/// ConvertedType. 760/// 761/// This routine also supports conversions to and from block pointers 762/// and conversions with Objective-C's 'id', 'id<protocols...>', and 763/// pointers to interfaces. FIXME: Once we've determined the 764/// appropriate overloading rules for Objective-C, we may want to 765/// split the Objective-C checks into a different routine; however, 766/// GCC seems to consider all of these conversions to be pointer 767/// conversions, so for now they live here. IncompatibleObjC will be 768/// set if the conversion is an allowed Objective-C conversion that 769/// should result in a warning. 770bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType, 771 QualType& ConvertedType, 772 bool &IncompatibleObjC) 773{ 774 IncompatibleObjC = false; 775 if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC)) 776 return true; 777 778 // Conversion from a null pointer constant to any Objective-C pointer type. 779 if (Context.isObjCObjectPointerType(ToType) && 780 From->isNullPointerConstant(Context)) { 781 ConvertedType = ToType; 782 return true; 783 } 784 785 // Blocks: Block pointers can be converted to void*. 786 if (FromType->isBlockPointerType() && ToType->isPointerType() && 787 ToType->getAsPointerType()->getPointeeType()->isVoidType()) { 788 ConvertedType = ToType; 789 return true; 790 } 791 // Blocks: A null pointer constant can be converted to a block 792 // pointer type. 793 if (ToType->isBlockPointerType() && From->isNullPointerConstant(Context)) { 794 ConvertedType = ToType; 795 return true; 796 } 797 798 const PointerType* ToTypePtr = ToType->getAsPointerType(); 799 if (!ToTypePtr) 800 return false; 801 802 // A null pointer constant can be converted to a pointer type (C++ 4.10p1). 803 if (From->isNullPointerConstant(Context)) { 804 ConvertedType = ToType; 805 return true; 806 } 807 808 // Beyond this point, both types need to be pointers. 809 const PointerType *FromTypePtr = FromType->getAsPointerType(); 810 if (!FromTypePtr) 811 return false; 812 813 QualType FromPointeeType = FromTypePtr->getPointeeType(); 814 QualType ToPointeeType = ToTypePtr->getPointeeType(); 815 816 // An rvalue of type "pointer to cv T," where T is an object type, 817 // can be converted to an rvalue of type "pointer to cv void" (C++ 818 // 4.10p2). 819 if (FromPointeeType->isIncompleteOrObjectType() && 820 ToPointeeType->isVoidType()) { 821 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 822 ToPointeeType, 823 ToType, Context); 824 return true; 825 } 826 827 // C++ [conv.ptr]p3: 828 // 829 // An rvalue of type "pointer to cv D," where D is a class type, 830 // can be converted to an rvalue of type "pointer to cv B," where 831 // B is a base class (clause 10) of D. If B is an inaccessible 832 // (clause 11) or ambiguous (10.2) base class of D, a program that 833 // necessitates this conversion is ill-formed. The result of the 834 // conversion is a pointer to the base class sub-object of the 835 // derived class object. The null pointer value is converted to 836 // the null pointer value of the destination type. 837 // 838 // Note that we do not check for ambiguity or inaccessibility 839 // here. That is handled by CheckPointerConversion. 840 if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 841 IsDerivedFrom(FromPointeeType, ToPointeeType)) { 842 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 843 ToPointeeType, 844 ToType, Context); 845 return true; 846 } 847 848 return false; 849} 850 851/// isObjCPointerConversion - Determines whether this is an 852/// Objective-C pointer conversion. Subroutine of IsPointerConversion, 853/// with the same arguments and return values. 854bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType, 855 QualType& ConvertedType, 856 bool &IncompatibleObjC) { 857 if (!getLangOptions().ObjC1) 858 return false; 859 860 // Conversions with Objective-C's id<...>. 861 if ((FromType->isObjCQualifiedIdType() || ToType->isObjCQualifiedIdType()) && 862 ObjCQualifiedIdTypesAreCompatible(ToType, FromType, /*compare=*/false)) { 863 ConvertedType = ToType; 864 return true; 865 } 866 867 // Beyond this point, both types need to be pointers or block pointers. 868 QualType ToPointeeType; 869 const PointerType* ToTypePtr = ToType->getAsPointerType(); 870 if (ToTypePtr) 871 ToPointeeType = ToTypePtr->getPointeeType(); 872 else if (const BlockPointerType *ToBlockPtr = ToType->getAsBlockPointerType()) 873 ToPointeeType = ToBlockPtr->getPointeeType(); 874 else 875 return false; 876 877 QualType FromPointeeType; 878 const PointerType *FromTypePtr = FromType->getAsPointerType(); 879 if (FromTypePtr) 880 FromPointeeType = FromTypePtr->getPointeeType(); 881 else if (const BlockPointerType *FromBlockPtr 882 = FromType->getAsBlockPointerType()) 883 FromPointeeType = FromBlockPtr->getPointeeType(); 884 else 885 return false; 886 887 // Objective C++: We're able to convert from a pointer to an 888 // interface to a pointer to a different interface. 889 const ObjCInterfaceType* FromIface = FromPointeeType->getAsObjCInterfaceType(); 890 const ObjCInterfaceType* ToIface = ToPointeeType->getAsObjCInterfaceType(); 891 if (FromIface && ToIface && 892 Context.canAssignObjCInterfaces(ToIface, FromIface)) { 893 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 894 ToPointeeType, 895 ToType, Context); 896 return true; 897 } 898 899 if (FromIface && ToIface && 900 Context.canAssignObjCInterfaces(FromIface, ToIface)) { 901 // Okay: this is some kind of implicit downcast of Objective-C 902 // interfaces, which is permitted. However, we're going to 903 // complain about it. 904 IncompatibleObjC = true; 905 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 906 ToPointeeType, 907 ToType, Context); 908 return true; 909 } 910 911 // Objective C++: We're able to convert between "id" and a pointer 912 // to any interface (in both directions). 913 if ((FromIface && Context.isObjCIdType(ToPointeeType)) 914 || (ToIface && Context.isObjCIdType(FromPointeeType))) { 915 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 916 ToPointeeType, 917 ToType, Context); 918 return true; 919 } 920 921 // Objective C++: Allow conversions between the Objective-C "id" and 922 // "Class", in either direction. 923 if ((Context.isObjCIdType(FromPointeeType) && 924 Context.isObjCClassType(ToPointeeType)) || 925 (Context.isObjCClassType(FromPointeeType) && 926 Context.isObjCIdType(ToPointeeType))) { 927 ConvertedType = ToType; 928 return true; 929 } 930 931 // If we have pointers to pointers, recursively check whether this 932 // is an Objective-C conversion. 933 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() && 934 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 935 IncompatibleObjC)) { 936 // We always complain about this conversion. 937 IncompatibleObjC = true; 938 ConvertedType = ToType; 939 return true; 940 } 941 942 // If we have pointers to functions or blocks, check whether the only 943 // differences in the argument and result types are in Objective-C 944 // pointer conversions. If so, we permit the conversion (but 945 // complain about it). 946 const FunctionTypeProto *FromFunctionType 947 = FromPointeeType->getAsFunctionTypeProto(); 948 const FunctionTypeProto *ToFunctionType 949 = ToPointeeType->getAsFunctionTypeProto(); 950 if (FromFunctionType && ToFunctionType) { 951 // If the function types are exactly the same, this isn't an 952 // Objective-C pointer conversion. 953 if (Context.getCanonicalType(FromPointeeType) 954 == Context.getCanonicalType(ToPointeeType)) 955 return false; 956 957 // Perform the quick checks that will tell us whether these 958 // function types are obviously different. 959 if (FromFunctionType->getNumArgs() != ToFunctionType->getNumArgs() || 960 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || 961 FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals()) 962 return false; 963 964 bool HasObjCConversion = false; 965 if (Context.getCanonicalType(FromFunctionType->getResultType()) 966 == Context.getCanonicalType(ToFunctionType->getResultType())) { 967 // Okay, the types match exactly. Nothing to do. 968 } else if (isObjCPointerConversion(FromFunctionType->getResultType(), 969 ToFunctionType->getResultType(), 970 ConvertedType, IncompatibleObjC)) { 971 // Okay, we have an Objective-C pointer conversion. 972 HasObjCConversion = true; 973 } else { 974 // Function types are too different. Abort. 975 return false; 976 } 977 978 // Check argument types. 979 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumArgs(); 980 ArgIdx != NumArgs; ++ArgIdx) { 981 QualType FromArgType = FromFunctionType->getArgType(ArgIdx); 982 QualType ToArgType = ToFunctionType->getArgType(ArgIdx); 983 if (Context.getCanonicalType(FromArgType) 984 == Context.getCanonicalType(ToArgType)) { 985 // Okay, the types match exactly. Nothing to do. 986 } else if (isObjCPointerConversion(FromArgType, ToArgType, 987 ConvertedType, IncompatibleObjC)) { 988 // Okay, we have an Objective-C pointer conversion. 989 HasObjCConversion = true; 990 } else { 991 // Argument types are too different. Abort. 992 return false; 993 } 994 } 995 996 if (HasObjCConversion) { 997 // We had an Objective-C conversion. Allow this pointer 998 // conversion, but complain about it. 999 ConvertedType = ToType; 1000 IncompatibleObjC = true; 1001 return true; 1002 } 1003 } 1004 1005 return false; 1006} 1007 1008/// CheckPointerConversion - Check the pointer conversion from the 1009/// expression From to the type ToType. This routine checks for 1010/// ambiguous (FIXME: or inaccessible) derived-to-base pointer 1011/// conversions for which IsPointerConversion has already returned 1012/// true. It returns true and produces a diagnostic if there was an 1013/// error, or returns false otherwise. 1014bool Sema::CheckPointerConversion(Expr *From, QualType ToType) { 1015 QualType FromType = From->getType(); 1016 1017 if (const PointerType *FromPtrType = FromType->getAsPointerType()) 1018 if (const PointerType *ToPtrType = ToType->getAsPointerType()) { 1019 QualType FromPointeeType = FromPtrType->getPointeeType(), 1020 ToPointeeType = ToPtrType->getPointeeType(); 1021 1022 // Objective-C++ conversions are always okay. 1023 // FIXME: We should have a different class of conversions for 1024 // the Objective-C++ implicit conversions. 1025 if (Context.isObjCIdType(FromPointeeType) || 1026 Context.isObjCIdType(ToPointeeType) || 1027 Context.isObjCClassType(FromPointeeType) || 1028 Context.isObjCClassType(ToPointeeType)) 1029 return false; 1030 1031 if (FromPointeeType->isRecordType() && 1032 ToPointeeType->isRecordType()) { 1033 // We must have a derived-to-base conversion. Check an 1034 // ambiguous or inaccessible conversion. 1035 return CheckDerivedToBaseConversion(FromPointeeType, ToPointeeType, 1036 From->getExprLoc(), 1037 From->getSourceRange()); 1038 } 1039 } 1040 1041 return false; 1042} 1043 1044/// IsMemberPointerConversion - Determines whether the conversion of the 1045/// expression From, which has the (possibly adjusted) type FromType, can be 1046/// converted to the type ToType via a member pointer conversion (C++ 4.11). 1047/// If so, returns true and places the converted type (that might differ from 1048/// ToType in its cv-qualifiers at some level) into ConvertedType. 1049bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType, 1050 QualType ToType, QualType &ConvertedType) 1051{ 1052 const MemberPointerType *ToTypePtr = ToType->getAsMemberPointerType(); 1053 if (!ToTypePtr) 1054 return false; 1055 1056 // A null pointer constant can be converted to a member pointer (C++ 4.11p1) 1057 if (From->isNullPointerConstant(Context)) { 1058 ConvertedType = ToType; 1059 return true; 1060 } 1061 1062 // Otherwise, both types have to be member pointers. 1063 const MemberPointerType *FromTypePtr = FromType->getAsMemberPointerType(); 1064 if (!FromTypePtr) 1065 return false; 1066 1067 // A pointer to member of B can be converted to a pointer to member of D, 1068 // where D is derived from B (C++ 4.11p2). 1069 QualType FromClass(FromTypePtr->getClass(), 0); 1070 QualType ToClass(ToTypePtr->getClass(), 0); 1071 // FIXME: What happens when these are dependent? Is this function even called? 1072 1073 if (IsDerivedFrom(ToClass, FromClass)) { 1074 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(), 1075 ToClass.getTypePtr()); 1076 return true; 1077 } 1078 1079 return false; 1080} 1081 1082/// CheckMemberPointerConversion - Check the member pointer conversion from the 1083/// expression From to the type ToType. This routine checks for ambiguous or 1084/// virtual (FIXME: or inaccessible) base-to-derived member pointer conversions 1085/// for which IsMemberPointerConversion has already returned true. It returns 1086/// true and produces a diagnostic if there was an error, or returns false 1087/// otherwise. 1088bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType) { 1089 QualType FromType = From->getType(); 1090 const MemberPointerType *FromPtrType = FromType->getAsMemberPointerType(); 1091 if (!FromPtrType) 1092 return false; 1093 1094 const MemberPointerType *ToPtrType = ToType->getAsMemberPointerType(); 1095 assert(ToPtrType && "No member pointer cast has a target type " 1096 "that is not a member pointer."); 1097 1098 QualType FromClass = QualType(FromPtrType->getClass(), 0); 1099 QualType ToClass = QualType(ToPtrType->getClass(), 0); 1100 1101 // FIXME: What about dependent types? 1102 assert(FromClass->isRecordType() && "Pointer into non-class."); 1103 assert(ToClass->isRecordType() && "Pointer into non-class."); 1104 1105 BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false, 1106 /*DetectVirtual=*/true); 1107 bool DerivationOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1108 assert(DerivationOkay && 1109 "Should not have been called if derivation isn't OK."); 1110 (void)DerivationOkay; 1111 1112 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). 1113 getUnqualifiedType())) { 1114 // Derivation is ambiguous. Redo the check to find the exact paths. 1115 Paths.clear(); 1116 Paths.setRecordingPaths(true); 1117 bool StillOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1118 assert(StillOkay && "Derivation changed due to quantum fluctuation."); 1119 (void)StillOkay; 1120 1121 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths); 1122 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv) 1123 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange(); 1124 return true; 1125 } 1126 1127 if (const CXXRecordType *VBase = Paths.getDetectedVirtual()) { 1128 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual) 1129 << FromClass << ToClass << QualType(VBase, 0) 1130 << From->getSourceRange(); 1131 return true; 1132 } 1133 1134 return false; 1135} 1136 1137/// IsQualificationConversion - Determines whether the conversion from 1138/// an rvalue of type FromType to ToType is a qualification conversion 1139/// (C++ 4.4). 1140bool 1141Sema::IsQualificationConversion(QualType FromType, QualType ToType) 1142{ 1143 FromType = Context.getCanonicalType(FromType); 1144 ToType = Context.getCanonicalType(ToType); 1145 1146 // If FromType and ToType are the same type, this is not a 1147 // qualification conversion. 1148 if (FromType == ToType) 1149 return false; 1150 1151 // (C++ 4.4p4): 1152 // A conversion can add cv-qualifiers at levels other than the first 1153 // in multi-level pointers, subject to the following rules: [...] 1154 bool PreviousToQualsIncludeConst = true; 1155 bool UnwrappedAnyPointer = false; 1156 while (UnwrapSimilarPointerTypes(FromType, ToType)) { 1157 // Within each iteration of the loop, we check the qualifiers to 1158 // determine if this still looks like a qualification 1159 // conversion. Then, if all is well, we unwrap one more level of 1160 // pointers or pointers-to-members and do it all again 1161 // until there are no more pointers or pointers-to-members left to 1162 // unwrap. 1163 UnwrappedAnyPointer = true; 1164 1165 // -- for every j > 0, if const is in cv 1,j then const is in cv 1166 // 2,j, and similarly for volatile. 1167 if (!ToType.isAtLeastAsQualifiedAs(FromType)) 1168 return false; 1169 1170 // -- if the cv 1,j and cv 2,j are different, then const is in 1171 // every cv for 0 < k < j. 1172 if (FromType.getCVRQualifiers() != ToType.getCVRQualifiers() 1173 && !PreviousToQualsIncludeConst) 1174 return false; 1175 1176 // Keep track of whether all prior cv-qualifiers in the "to" type 1177 // include const. 1178 PreviousToQualsIncludeConst 1179 = PreviousToQualsIncludeConst && ToType.isConstQualified(); 1180 } 1181 1182 // We are left with FromType and ToType being the pointee types 1183 // after unwrapping the original FromType and ToType the same number 1184 // of types. If we unwrapped any pointers, and if FromType and 1185 // ToType have the same unqualified type (since we checked 1186 // qualifiers above), then this is a qualification conversion. 1187 return UnwrappedAnyPointer && 1188 FromType.getUnqualifiedType() == ToType.getUnqualifiedType(); 1189} 1190 1191/// IsUserDefinedConversion - Determines whether there is a 1192/// user-defined conversion sequence (C++ [over.ics.user]) that 1193/// converts expression From to the type ToType. If such a conversion 1194/// exists, User will contain the user-defined conversion sequence 1195/// that performs such a conversion and this routine will return 1196/// true. Otherwise, this routine returns false and User is 1197/// unspecified. AllowExplicit is true if the conversion should 1198/// consider C++0x "explicit" conversion functions as well as 1199/// non-explicit conversion functions (C++0x [class.conv.fct]p2). 1200bool Sema::IsUserDefinedConversion(Expr *From, QualType ToType, 1201 UserDefinedConversionSequence& User, 1202 bool AllowExplicit) 1203{ 1204 OverloadCandidateSet CandidateSet; 1205 if (const CXXRecordType *ToRecordType 1206 = dyn_cast_or_null<CXXRecordType>(ToType->getAsRecordType())) { 1207 // C++ [over.match.ctor]p1: 1208 // When objects of class type are direct-initialized (8.5), or 1209 // copy-initialized from an expression of the same or a 1210 // derived class type (8.5), overload resolution selects the 1211 // constructor. [...] For copy-initialization, the candidate 1212 // functions are all the converting constructors (12.3.1) of 1213 // that class. The argument list is the expression-list within 1214 // the parentheses of the initializer. 1215 CXXRecordDecl *ToRecordDecl = ToRecordType->getDecl(); 1216 DeclarationName ConstructorName 1217 = Context.DeclarationNames.getCXXConstructorName( 1218 Context.getCanonicalType(ToType).getUnqualifiedType()); 1219 DeclContext::lookup_iterator Con, ConEnd; 1220 for (llvm::tie(Con, ConEnd) = ToRecordDecl->lookup(ConstructorName); 1221 Con != ConEnd; ++Con) { 1222 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(*Con); 1223 if (Constructor->isConvertingConstructor()) 1224 AddOverloadCandidate(Constructor, &From, 1, CandidateSet, 1225 /*SuppressUserConversions=*/true); 1226 } 1227 } 1228 1229 if (const CXXRecordType *FromRecordType 1230 = dyn_cast_or_null<CXXRecordType>(From->getType()->getAsRecordType())) { 1231 // Add all of the conversion functions as candidates. 1232 // FIXME: Look for conversions in base classes! 1233 CXXRecordDecl *FromRecordDecl = FromRecordType->getDecl(); 1234 OverloadedFunctionDecl *Conversions 1235 = FromRecordDecl->getConversionFunctions(); 1236 for (OverloadedFunctionDecl::function_iterator Func 1237 = Conversions->function_begin(); 1238 Func != Conversions->function_end(); ++Func) { 1239 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func); 1240 if (AllowExplicit || !Conv->isExplicit()) 1241 AddConversionCandidate(Conv, From, ToType, CandidateSet); 1242 } 1243 } 1244 1245 OverloadCandidateSet::iterator Best; 1246 switch (BestViableFunction(CandidateSet, Best)) { 1247 case OR_Success: 1248 // Record the standard conversion we used and the conversion function. 1249 if (CXXConstructorDecl *Constructor 1250 = dyn_cast<CXXConstructorDecl>(Best->Function)) { 1251 // C++ [over.ics.user]p1: 1252 // If the user-defined conversion is specified by a 1253 // constructor (12.3.1), the initial standard conversion 1254 // sequence converts the source type to the type required by 1255 // the argument of the constructor. 1256 // 1257 // FIXME: What about ellipsis conversions? 1258 QualType ThisType = Constructor->getThisType(Context); 1259 User.Before = Best->Conversions[0].Standard; 1260 User.ConversionFunction = Constructor; 1261 User.After.setAsIdentityConversion(); 1262 User.After.FromTypePtr 1263 = ThisType->getAsPointerType()->getPointeeType().getAsOpaquePtr(); 1264 User.After.ToTypePtr = ToType.getAsOpaquePtr(); 1265 return true; 1266 } else if (CXXConversionDecl *Conversion 1267 = dyn_cast<CXXConversionDecl>(Best->Function)) { 1268 // C++ [over.ics.user]p1: 1269 // 1270 // [...] If the user-defined conversion is specified by a 1271 // conversion function (12.3.2), the initial standard 1272 // conversion sequence converts the source type to the 1273 // implicit object parameter of the conversion function. 1274 User.Before = Best->Conversions[0].Standard; 1275 User.ConversionFunction = Conversion; 1276 1277 // C++ [over.ics.user]p2: 1278 // The second standard conversion sequence converts the 1279 // result of the user-defined conversion to the target type 1280 // for the sequence. Since an implicit conversion sequence 1281 // is an initialization, the special rules for 1282 // initialization by user-defined conversion apply when 1283 // selecting the best user-defined conversion for a 1284 // user-defined conversion sequence (see 13.3.3 and 1285 // 13.3.3.1). 1286 User.After = Best->FinalConversion; 1287 return true; 1288 } else { 1289 assert(false && "Not a constructor or conversion function?"); 1290 return false; 1291 } 1292 1293 case OR_No_Viable_Function: 1294 // No conversion here! We're done. 1295 return false; 1296 1297 case OR_Ambiguous: 1298 // FIXME: See C++ [over.best.ics]p10 for the handling of 1299 // ambiguous conversion sequences. 1300 return false; 1301 } 1302 1303 return false; 1304} 1305 1306/// CompareImplicitConversionSequences - Compare two implicit 1307/// conversion sequences to determine whether one is better than the 1308/// other or if they are indistinguishable (C++ 13.3.3.2). 1309ImplicitConversionSequence::CompareKind 1310Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1, 1311 const ImplicitConversionSequence& ICS2) 1312{ 1313 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit 1314 // conversion sequences (as defined in 13.3.3.1) 1315 // -- a standard conversion sequence (13.3.3.1.1) is a better 1316 // conversion sequence than a user-defined conversion sequence or 1317 // an ellipsis conversion sequence, and 1318 // -- a user-defined conversion sequence (13.3.3.1.2) is a better 1319 // conversion sequence than an ellipsis conversion sequence 1320 // (13.3.3.1.3). 1321 // 1322 if (ICS1.ConversionKind < ICS2.ConversionKind) 1323 return ImplicitConversionSequence::Better; 1324 else if (ICS2.ConversionKind < ICS1.ConversionKind) 1325 return ImplicitConversionSequence::Worse; 1326 1327 // Two implicit conversion sequences of the same form are 1328 // indistinguishable conversion sequences unless one of the 1329 // following rules apply: (C++ 13.3.3.2p3): 1330 if (ICS1.ConversionKind == ImplicitConversionSequence::StandardConversion) 1331 return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard); 1332 else if (ICS1.ConversionKind == 1333 ImplicitConversionSequence::UserDefinedConversion) { 1334 // User-defined conversion sequence U1 is a better conversion 1335 // sequence than another user-defined conversion sequence U2 if 1336 // they contain the same user-defined conversion function or 1337 // constructor and if the second standard conversion sequence of 1338 // U1 is better than the second standard conversion sequence of 1339 // U2 (C++ 13.3.3.2p3). 1340 if (ICS1.UserDefined.ConversionFunction == 1341 ICS2.UserDefined.ConversionFunction) 1342 return CompareStandardConversionSequences(ICS1.UserDefined.After, 1343 ICS2.UserDefined.After); 1344 } 1345 1346 return ImplicitConversionSequence::Indistinguishable; 1347} 1348 1349/// CompareStandardConversionSequences - Compare two standard 1350/// conversion sequences to determine whether one is better than the 1351/// other or if they are indistinguishable (C++ 13.3.3.2p3). 1352ImplicitConversionSequence::CompareKind 1353Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1, 1354 const StandardConversionSequence& SCS2) 1355{ 1356 // Standard conversion sequence S1 is a better conversion sequence 1357 // than standard conversion sequence S2 if (C++ 13.3.3.2p3): 1358 1359 // -- S1 is a proper subsequence of S2 (comparing the conversion 1360 // sequences in the canonical form defined by 13.3.3.1.1, 1361 // excluding any Lvalue Transformation; the identity conversion 1362 // sequence is considered to be a subsequence of any 1363 // non-identity conversion sequence) or, if not that, 1364 if (SCS1.Second == SCS2.Second && SCS1.Third == SCS2.Third) 1365 // Neither is a proper subsequence of the other. Do nothing. 1366 ; 1367 else if ((SCS1.Second == ICK_Identity && SCS1.Third == SCS2.Third) || 1368 (SCS1.Third == ICK_Identity && SCS1.Second == SCS2.Second) || 1369 (SCS1.Second == ICK_Identity && 1370 SCS1.Third == ICK_Identity)) 1371 // SCS1 is a proper subsequence of SCS2. 1372 return ImplicitConversionSequence::Better; 1373 else if ((SCS2.Second == ICK_Identity && SCS2.Third == SCS1.Third) || 1374 (SCS2.Third == ICK_Identity && SCS2.Second == SCS1.Second) || 1375 (SCS2.Second == ICK_Identity && 1376 SCS2.Third == ICK_Identity)) 1377 // SCS2 is a proper subsequence of SCS1. 1378 return ImplicitConversionSequence::Worse; 1379 1380 // -- the rank of S1 is better than the rank of S2 (by the rules 1381 // defined below), or, if not that, 1382 ImplicitConversionRank Rank1 = SCS1.getRank(); 1383 ImplicitConversionRank Rank2 = SCS2.getRank(); 1384 if (Rank1 < Rank2) 1385 return ImplicitConversionSequence::Better; 1386 else if (Rank2 < Rank1) 1387 return ImplicitConversionSequence::Worse; 1388 1389 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank 1390 // are indistinguishable unless one of the following rules 1391 // applies: 1392 1393 // A conversion that is not a conversion of a pointer, or 1394 // pointer to member, to bool is better than another conversion 1395 // that is such a conversion. 1396 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool()) 1397 return SCS2.isPointerConversionToBool() 1398 ? ImplicitConversionSequence::Better 1399 : ImplicitConversionSequence::Worse; 1400 1401 // C++ [over.ics.rank]p4b2: 1402 // 1403 // If class B is derived directly or indirectly from class A, 1404 // conversion of B* to A* is better than conversion of B* to 1405 // void*, and conversion of A* to void* is better than conversion 1406 // of B* to void*. 1407 bool SCS1ConvertsToVoid 1408 = SCS1.isPointerConversionToVoidPointer(Context); 1409 bool SCS2ConvertsToVoid 1410 = SCS2.isPointerConversionToVoidPointer(Context); 1411 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) { 1412 // Exactly one of the conversion sequences is a conversion to 1413 // a void pointer; it's the worse conversion. 1414 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better 1415 : ImplicitConversionSequence::Worse; 1416 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) { 1417 // Neither conversion sequence converts to a void pointer; compare 1418 // their derived-to-base conversions. 1419 if (ImplicitConversionSequence::CompareKind DerivedCK 1420 = CompareDerivedToBaseConversions(SCS1, SCS2)) 1421 return DerivedCK; 1422 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid) { 1423 // Both conversion sequences are conversions to void 1424 // pointers. Compare the source types to determine if there's an 1425 // inheritance relationship in their sources. 1426 QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr); 1427 QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr); 1428 1429 // Adjust the types we're converting from via the array-to-pointer 1430 // conversion, if we need to. 1431 if (SCS1.First == ICK_Array_To_Pointer) 1432 FromType1 = Context.getArrayDecayedType(FromType1); 1433 if (SCS2.First == ICK_Array_To_Pointer) 1434 FromType2 = Context.getArrayDecayedType(FromType2); 1435 1436 QualType FromPointee1 1437 = FromType1->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1438 QualType FromPointee2 1439 = FromType2->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1440 1441 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1442 return ImplicitConversionSequence::Better; 1443 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1444 return ImplicitConversionSequence::Worse; 1445 1446 // Objective-C++: If one interface is more specific than the 1447 // other, it is the better one. 1448 const ObjCInterfaceType* FromIface1 = FromPointee1->getAsObjCInterfaceType(); 1449 const ObjCInterfaceType* FromIface2 = FromPointee2->getAsObjCInterfaceType(); 1450 if (FromIface1 && FromIface1) { 1451 if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1452 return ImplicitConversionSequence::Better; 1453 else if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1454 return ImplicitConversionSequence::Worse; 1455 } 1456 } 1457 1458 // Compare based on qualification conversions (C++ 13.3.3.2p3, 1459 // bullet 3). 1460 if (ImplicitConversionSequence::CompareKind QualCK 1461 = CompareQualificationConversions(SCS1, SCS2)) 1462 return QualCK; 1463 1464 // C++ [over.ics.rank]p3b4: 1465 // -- S1 and S2 are reference bindings (8.5.3), and the types to 1466 // which the references refer are the same type except for 1467 // top-level cv-qualifiers, and the type to which the reference 1468 // initialized by S2 refers is more cv-qualified than the type 1469 // to which the reference initialized by S1 refers. 1470 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { 1471 QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1472 QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1473 T1 = Context.getCanonicalType(T1); 1474 T2 = Context.getCanonicalType(T2); 1475 if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) { 1476 if (T2.isMoreQualifiedThan(T1)) 1477 return ImplicitConversionSequence::Better; 1478 else if (T1.isMoreQualifiedThan(T2)) 1479 return ImplicitConversionSequence::Worse; 1480 } 1481 } 1482 1483 return ImplicitConversionSequence::Indistinguishable; 1484} 1485 1486/// CompareQualificationConversions - Compares two standard conversion 1487/// sequences to determine whether they can be ranked based on their 1488/// qualification conversions (C++ 13.3.3.2p3 bullet 3). 1489ImplicitConversionSequence::CompareKind 1490Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1, 1491 const StandardConversionSequence& SCS2) 1492{ 1493 // C++ 13.3.3.2p3: 1494 // -- S1 and S2 differ only in their qualification conversion and 1495 // yield similar types T1 and T2 (C++ 4.4), respectively, and the 1496 // cv-qualification signature of type T1 is a proper subset of 1497 // the cv-qualification signature of type T2, and S1 is not the 1498 // deprecated string literal array-to-pointer conversion (4.2). 1499 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second || 1500 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification) 1501 return ImplicitConversionSequence::Indistinguishable; 1502 1503 // FIXME: the example in the standard doesn't use a qualification 1504 // conversion (!) 1505 QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1506 QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1507 T1 = Context.getCanonicalType(T1); 1508 T2 = Context.getCanonicalType(T2); 1509 1510 // If the types are the same, we won't learn anything by unwrapped 1511 // them. 1512 if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) 1513 return ImplicitConversionSequence::Indistinguishable; 1514 1515 ImplicitConversionSequence::CompareKind Result 1516 = ImplicitConversionSequence::Indistinguishable; 1517 while (UnwrapSimilarPointerTypes(T1, T2)) { 1518 // Within each iteration of the loop, we check the qualifiers to 1519 // determine if this still looks like a qualification 1520 // conversion. Then, if all is well, we unwrap one more level of 1521 // pointers or pointers-to-members and do it all again 1522 // until there are no more pointers or pointers-to-members left 1523 // to unwrap. This essentially mimics what 1524 // IsQualificationConversion does, but here we're checking for a 1525 // strict subset of qualifiers. 1526 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 1527 // The qualifiers are the same, so this doesn't tell us anything 1528 // about how the sequences rank. 1529 ; 1530 else if (T2.isMoreQualifiedThan(T1)) { 1531 // T1 has fewer qualifiers, so it could be the better sequence. 1532 if (Result == ImplicitConversionSequence::Worse) 1533 // Neither has qualifiers that are a subset of the other's 1534 // qualifiers. 1535 return ImplicitConversionSequence::Indistinguishable; 1536 1537 Result = ImplicitConversionSequence::Better; 1538 } else if (T1.isMoreQualifiedThan(T2)) { 1539 // T2 has fewer qualifiers, so it could be the better sequence. 1540 if (Result == ImplicitConversionSequence::Better) 1541 // Neither has qualifiers that are a subset of the other's 1542 // qualifiers. 1543 return ImplicitConversionSequence::Indistinguishable; 1544 1545 Result = ImplicitConversionSequence::Worse; 1546 } else { 1547 // Qualifiers are disjoint. 1548 return ImplicitConversionSequence::Indistinguishable; 1549 } 1550 1551 // If the types after this point are equivalent, we're done. 1552 if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) 1553 break; 1554 } 1555 1556 // Check that the winning standard conversion sequence isn't using 1557 // the deprecated string literal array to pointer conversion. 1558 switch (Result) { 1559 case ImplicitConversionSequence::Better: 1560 if (SCS1.Deprecated) 1561 Result = ImplicitConversionSequence::Indistinguishable; 1562 break; 1563 1564 case ImplicitConversionSequence::Indistinguishable: 1565 break; 1566 1567 case ImplicitConversionSequence::Worse: 1568 if (SCS2.Deprecated) 1569 Result = ImplicitConversionSequence::Indistinguishable; 1570 break; 1571 } 1572 1573 return Result; 1574} 1575 1576/// CompareDerivedToBaseConversions - Compares two standard conversion 1577/// sequences to determine whether they can be ranked based on their 1578/// various kinds of derived-to-base conversions (C++ 1579/// [over.ics.rank]p4b3). As part of these checks, we also look at 1580/// conversions between Objective-C interface types. 1581ImplicitConversionSequence::CompareKind 1582Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1, 1583 const StandardConversionSequence& SCS2) { 1584 QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr); 1585 QualType ToType1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1586 QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr); 1587 QualType ToType2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1588 1589 // Adjust the types we're converting from via the array-to-pointer 1590 // conversion, if we need to. 1591 if (SCS1.First == ICK_Array_To_Pointer) 1592 FromType1 = Context.getArrayDecayedType(FromType1); 1593 if (SCS2.First == ICK_Array_To_Pointer) 1594 FromType2 = Context.getArrayDecayedType(FromType2); 1595 1596 // Canonicalize all of the types. 1597 FromType1 = Context.getCanonicalType(FromType1); 1598 ToType1 = Context.getCanonicalType(ToType1); 1599 FromType2 = Context.getCanonicalType(FromType2); 1600 ToType2 = Context.getCanonicalType(ToType2); 1601 1602 // C++ [over.ics.rank]p4b3: 1603 // 1604 // If class B is derived directly or indirectly from class A and 1605 // class C is derived directly or indirectly from B, 1606 // 1607 // For Objective-C, we let A, B, and C also be Objective-C 1608 // interfaces. 1609 1610 // Compare based on pointer conversions. 1611 if (SCS1.Second == ICK_Pointer_Conversion && 1612 SCS2.Second == ICK_Pointer_Conversion && 1613 /*FIXME: Remove if Objective-C id conversions get their own rank*/ 1614 FromType1->isPointerType() && FromType2->isPointerType() && 1615 ToType1->isPointerType() && ToType2->isPointerType()) { 1616 QualType FromPointee1 1617 = FromType1->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1618 QualType ToPointee1 1619 = ToType1->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1620 QualType FromPointee2 1621 = FromType2->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1622 QualType ToPointee2 1623 = ToType2->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1624 1625 const ObjCInterfaceType* FromIface1 = FromPointee1->getAsObjCInterfaceType(); 1626 const ObjCInterfaceType* FromIface2 = FromPointee2->getAsObjCInterfaceType(); 1627 const ObjCInterfaceType* ToIface1 = ToPointee1->getAsObjCInterfaceType(); 1628 const ObjCInterfaceType* ToIface2 = ToPointee2->getAsObjCInterfaceType(); 1629 1630 // -- conversion of C* to B* is better than conversion of C* to A*, 1631 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 1632 if (IsDerivedFrom(ToPointee1, ToPointee2)) 1633 return ImplicitConversionSequence::Better; 1634 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 1635 return ImplicitConversionSequence::Worse; 1636 1637 if (ToIface1 && ToIface2) { 1638 if (Context.canAssignObjCInterfaces(ToIface2, ToIface1)) 1639 return ImplicitConversionSequence::Better; 1640 else if (Context.canAssignObjCInterfaces(ToIface1, ToIface2)) 1641 return ImplicitConversionSequence::Worse; 1642 } 1643 } 1644 1645 // -- conversion of B* to A* is better than conversion of C* to A*, 1646 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { 1647 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1648 return ImplicitConversionSequence::Better; 1649 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1650 return ImplicitConversionSequence::Worse; 1651 1652 if (FromIface1 && FromIface2) { 1653 if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1654 return ImplicitConversionSequence::Better; 1655 else if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1656 return ImplicitConversionSequence::Worse; 1657 } 1658 } 1659 } 1660 1661 // Compare based on reference bindings. 1662 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding && 1663 SCS1.Second == ICK_Derived_To_Base) { 1664 // -- binding of an expression of type C to a reference of type 1665 // B& is better than binding an expression of type C to a 1666 // reference of type A&, 1667 if (FromType1.getUnqualifiedType() == FromType2.getUnqualifiedType() && 1668 ToType1.getUnqualifiedType() != ToType2.getUnqualifiedType()) { 1669 if (IsDerivedFrom(ToType1, ToType2)) 1670 return ImplicitConversionSequence::Better; 1671 else if (IsDerivedFrom(ToType2, ToType1)) 1672 return ImplicitConversionSequence::Worse; 1673 } 1674 1675 // -- binding of an expression of type B to a reference of type 1676 // A& is better than binding an expression of type C to a 1677 // reference of type A&, 1678 if (FromType1.getUnqualifiedType() != FromType2.getUnqualifiedType() && 1679 ToType1.getUnqualifiedType() == ToType2.getUnqualifiedType()) { 1680 if (IsDerivedFrom(FromType2, FromType1)) 1681 return ImplicitConversionSequence::Better; 1682 else if (IsDerivedFrom(FromType1, FromType2)) 1683 return ImplicitConversionSequence::Worse; 1684 } 1685 } 1686 1687 1688 // FIXME: conversion of A::* to B::* is better than conversion of 1689 // A::* to C::*, 1690 1691 // FIXME: conversion of B::* to C::* is better than conversion of 1692 // A::* to C::*, and 1693 1694 if (SCS1.CopyConstructor && SCS2.CopyConstructor && 1695 SCS1.Second == ICK_Derived_To_Base) { 1696 // -- conversion of C to B is better than conversion of C to A, 1697 if (FromType1.getUnqualifiedType() == FromType2.getUnqualifiedType() && 1698 ToType1.getUnqualifiedType() != ToType2.getUnqualifiedType()) { 1699 if (IsDerivedFrom(ToType1, ToType2)) 1700 return ImplicitConversionSequence::Better; 1701 else if (IsDerivedFrom(ToType2, ToType1)) 1702 return ImplicitConversionSequence::Worse; 1703 } 1704 1705 // -- conversion of B to A is better than conversion of C to A. 1706 if (FromType1.getUnqualifiedType() != FromType2.getUnqualifiedType() && 1707 ToType1.getUnqualifiedType() == ToType2.getUnqualifiedType()) { 1708 if (IsDerivedFrom(FromType2, FromType1)) 1709 return ImplicitConversionSequence::Better; 1710 else if (IsDerivedFrom(FromType1, FromType2)) 1711 return ImplicitConversionSequence::Worse; 1712 } 1713 } 1714 1715 return ImplicitConversionSequence::Indistinguishable; 1716} 1717 1718/// TryCopyInitialization - Try to copy-initialize a value of type 1719/// ToType from the expression From. Return the implicit conversion 1720/// sequence required to pass this argument, which may be a bad 1721/// conversion sequence (meaning that the argument cannot be passed to 1722/// a parameter of this type). If @p SuppressUserConversions, then we 1723/// do not permit any user-defined conversion sequences. 1724ImplicitConversionSequence 1725Sema::TryCopyInitialization(Expr *From, QualType ToType, 1726 bool SuppressUserConversions) { 1727 if (!getLangOptions().CPlusPlus) { 1728 // In C, copy initialization is the same as performing an assignment. 1729 AssignConvertType ConvTy = 1730 CheckSingleAssignmentConstraints(ToType, From); 1731 ImplicitConversionSequence ICS; 1732 if (getLangOptions().NoExtensions? ConvTy != Compatible 1733 : ConvTy == Incompatible) 1734 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 1735 else 1736 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 1737 return ICS; 1738 } else if (ToType->isReferenceType()) { 1739 ImplicitConversionSequence ICS; 1740 CheckReferenceInit(From, ToType, &ICS, SuppressUserConversions); 1741 return ICS; 1742 } else { 1743 return TryImplicitConversion(From, ToType, SuppressUserConversions); 1744 } 1745} 1746 1747/// PerformArgumentPassing - Pass the argument Arg into a parameter of 1748/// type ToType. Returns true (and emits a diagnostic) if there was 1749/// an error, returns false if the initialization succeeded. 1750bool Sema::PerformCopyInitialization(Expr *&From, QualType ToType, 1751 const char* Flavor) { 1752 if (!getLangOptions().CPlusPlus) { 1753 // In C, argument passing is the same as performing an assignment. 1754 QualType FromType = From->getType(); 1755 AssignConvertType ConvTy = 1756 CheckSingleAssignmentConstraints(ToType, From); 1757 1758 return DiagnoseAssignmentResult(ConvTy, From->getLocStart(), ToType, 1759 FromType, From, Flavor); 1760 } 1761 1762 if (ToType->isReferenceType()) 1763 return CheckReferenceInit(From, ToType); 1764 1765 if (!PerformImplicitConversion(From, ToType, Flavor)) 1766 return false; 1767 1768 return Diag(From->getSourceRange().getBegin(), 1769 diag::err_typecheck_convert_incompatible) 1770 << ToType << From->getType() << Flavor << From->getSourceRange(); 1771} 1772 1773/// TryObjectArgumentInitialization - Try to initialize the object 1774/// parameter of the given member function (@c Method) from the 1775/// expression @p From. 1776ImplicitConversionSequence 1777Sema::TryObjectArgumentInitialization(Expr *From, CXXMethodDecl *Method) { 1778 QualType ClassType = Context.getTypeDeclType(Method->getParent()); 1779 unsigned MethodQuals = Method->getTypeQualifiers(); 1780 QualType ImplicitParamType = ClassType.getQualifiedType(MethodQuals); 1781 1782 // Set up the conversion sequence as a "bad" conversion, to allow us 1783 // to exit early. 1784 ImplicitConversionSequence ICS; 1785 ICS.Standard.setAsIdentityConversion(); 1786 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 1787 1788 // We need to have an object of class type. 1789 QualType FromType = From->getType(); 1790 if (!FromType->isRecordType()) 1791 return ICS; 1792 1793 // The implicit object parmeter is has the type "reference to cv X", 1794 // where X is the class of which the function is a member 1795 // (C++ [over.match.funcs]p4). However, when finding an implicit 1796 // conversion sequence for the argument, we are not allowed to 1797 // create temporaries or perform user-defined conversions 1798 // (C++ [over.match.funcs]p5). We perform a simplified version of 1799 // reference binding here, that allows class rvalues to bind to 1800 // non-constant references. 1801 1802 // First check the qualifiers. We don't care about lvalue-vs-rvalue 1803 // with the implicit object parameter (C++ [over.match.funcs]p5). 1804 QualType FromTypeCanon = Context.getCanonicalType(FromType); 1805 if (ImplicitParamType.getCVRQualifiers() != FromType.getCVRQualifiers() && 1806 !ImplicitParamType.isAtLeastAsQualifiedAs(FromType)) 1807 return ICS; 1808 1809 // Check that we have either the same type or a derived type. It 1810 // affects the conversion rank. 1811 QualType ClassTypeCanon = Context.getCanonicalType(ClassType); 1812 if (ClassTypeCanon == FromTypeCanon.getUnqualifiedType()) 1813 ICS.Standard.Second = ICK_Identity; 1814 else if (IsDerivedFrom(FromType, ClassType)) 1815 ICS.Standard.Second = ICK_Derived_To_Base; 1816 else 1817 return ICS; 1818 1819 // Success. Mark this as a reference binding. 1820 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 1821 ICS.Standard.FromTypePtr = FromType.getAsOpaquePtr(); 1822 ICS.Standard.ToTypePtr = ImplicitParamType.getAsOpaquePtr(); 1823 ICS.Standard.ReferenceBinding = true; 1824 ICS.Standard.DirectBinding = true; 1825 return ICS; 1826} 1827 1828/// PerformObjectArgumentInitialization - Perform initialization of 1829/// the implicit object parameter for the given Method with the given 1830/// expression. 1831bool 1832Sema::PerformObjectArgumentInitialization(Expr *&From, CXXMethodDecl *Method) { 1833 QualType ImplicitParamType 1834 = Method->getThisType(Context)->getAsPointerType()->getPointeeType(); 1835 ImplicitConversionSequence ICS 1836 = TryObjectArgumentInitialization(From, Method); 1837 if (ICS.ConversionKind == ImplicitConversionSequence::BadConversion) 1838 return Diag(From->getSourceRange().getBegin(), 1839 diag::err_implicit_object_parameter_init) 1840 << ImplicitParamType << From->getType() << From->getSourceRange(); 1841 1842 if (ICS.Standard.Second == ICK_Derived_To_Base && 1843 CheckDerivedToBaseConversion(From->getType(), ImplicitParamType, 1844 From->getSourceRange().getBegin(), 1845 From->getSourceRange())) 1846 return true; 1847 1848 ImpCastExprToType(From, ImplicitParamType, /*isLvalue=*/true); 1849 return false; 1850} 1851 1852/// TryContextuallyConvertToBool - Attempt to contextually convert the 1853/// expression From to bool (C++0x [conv]p3). 1854ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) { 1855 return TryImplicitConversion(From, Context.BoolTy, false, true); 1856} 1857 1858/// PerformContextuallyConvertToBool - Perform a contextual conversion 1859/// of the expression From to bool (C++0x [conv]p3). 1860bool Sema::PerformContextuallyConvertToBool(Expr *&From) { 1861 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From); 1862 if (!PerformImplicitConversion(From, Context.BoolTy, ICS, "converting")) 1863 return false; 1864 1865 return Diag(From->getSourceRange().getBegin(), 1866 diag::err_typecheck_bool_condition) 1867 << From->getType() << From->getSourceRange(); 1868} 1869 1870/// AddOverloadCandidate - Adds the given function to the set of 1871/// candidate functions, using the given function call arguments. If 1872/// @p SuppressUserConversions, then don't allow user-defined 1873/// conversions via constructors or conversion operators. 1874void 1875Sema::AddOverloadCandidate(FunctionDecl *Function, 1876 Expr **Args, unsigned NumArgs, 1877 OverloadCandidateSet& CandidateSet, 1878 bool SuppressUserConversions) 1879{ 1880 const FunctionTypeProto* Proto 1881 = dyn_cast<FunctionTypeProto>(Function->getType()->getAsFunctionType()); 1882 assert(Proto && "Functions without a prototype cannot be overloaded"); 1883 assert(!isa<CXXConversionDecl>(Function) && 1884 "Use AddConversionCandidate for conversion functions"); 1885 1886 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 1887 // If we get here, it's because we're calling a member function 1888 // that is named without a member access expression (e.g., 1889 // "this->f") that was either written explicitly or created 1890 // implicitly. This can happen with a qualified call to a member 1891 // function, e.g., X::f(). We use a NULL object as the implied 1892 // object argument (C++ [over.call.func]p3). 1893 AddMethodCandidate(Method, 0, Args, NumArgs, CandidateSet, 1894 SuppressUserConversions); 1895 return; 1896 } 1897 1898 1899 // Add this candidate 1900 CandidateSet.push_back(OverloadCandidate()); 1901 OverloadCandidate& Candidate = CandidateSet.back(); 1902 Candidate.Function = Function; 1903 Candidate.Viable = true; 1904 Candidate.IsSurrogate = false; 1905 Candidate.IgnoreObjectArgument = false; 1906 1907 unsigned NumArgsInProto = Proto->getNumArgs(); 1908 1909 // (C++ 13.3.2p2): A candidate function having fewer than m 1910 // parameters is viable only if it has an ellipsis in its parameter 1911 // list (8.3.5). 1912 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 1913 Candidate.Viable = false; 1914 return; 1915 } 1916 1917 // (C++ 13.3.2p2): A candidate function having more than m parameters 1918 // is viable only if the (m+1)st parameter has a default argument 1919 // (8.3.6). For the purposes of overload resolution, the 1920 // parameter list is truncated on the right, so that there are 1921 // exactly m parameters. 1922 unsigned MinRequiredArgs = Function->getMinRequiredArguments(); 1923 if (NumArgs < MinRequiredArgs) { 1924 // Not enough arguments. 1925 Candidate.Viable = false; 1926 return; 1927 } 1928 1929 // Determine the implicit conversion sequences for each of the 1930 // arguments. 1931 Candidate.Conversions.resize(NumArgs); 1932 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 1933 if (ArgIdx < NumArgsInProto) { 1934 // (C++ 13.3.2p3): for F to be a viable function, there shall 1935 // exist for each argument an implicit conversion sequence 1936 // (13.3.3.1) that converts that argument to the corresponding 1937 // parameter of F. 1938 QualType ParamType = Proto->getArgType(ArgIdx); 1939 Candidate.Conversions[ArgIdx] 1940 = TryCopyInitialization(Args[ArgIdx], ParamType, 1941 SuppressUserConversions); 1942 if (Candidate.Conversions[ArgIdx].ConversionKind 1943 == ImplicitConversionSequence::BadConversion) { 1944 Candidate.Viable = false; 1945 break; 1946 } 1947 } else { 1948 // (C++ 13.3.2p2): For the purposes of overload resolution, any 1949 // argument for which there is no corresponding parameter is 1950 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 1951 Candidate.Conversions[ArgIdx].ConversionKind 1952 = ImplicitConversionSequence::EllipsisConversion; 1953 } 1954 } 1955} 1956 1957/// AddMethodCandidate - Adds the given C++ member function to the set 1958/// of candidate functions, using the given function call arguments 1959/// and the object argument (@c Object). For example, in a call 1960/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain 1961/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't 1962/// allow user-defined conversions via constructors or conversion 1963/// operators. 1964void 1965Sema::AddMethodCandidate(CXXMethodDecl *Method, Expr *Object, 1966 Expr **Args, unsigned NumArgs, 1967 OverloadCandidateSet& CandidateSet, 1968 bool SuppressUserConversions) 1969{ 1970 const FunctionTypeProto* Proto 1971 = dyn_cast<FunctionTypeProto>(Method->getType()->getAsFunctionType()); 1972 assert(Proto && "Methods without a prototype cannot be overloaded"); 1973 assert(!isa<CXXConversionDecl>(Method) && 1974 "Use AddConversionCandidate for conversion functions"); 1975 1976 // Add this candidate 1977 CandidateSet.push_back(OverloadCandidate()); 1978 OverloadCandidate& Candidate = CandidateSet.back(); 1979 Candidate.Function = Method; 1980 Candidate.IsSurrogate = false; 1981 Candidate.IgnoreObjectArgument = false; 1982 1983 unsigned NumArgsInProto = Proto->getNumArgs(); 1984 1985 // (C++ 13.3.2p2): A candidate function having fewer than m 1986 // parameters is viable only if it has an ellipsis in its parameter 1987 // list (8.3.5). 1988 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 1989 Candidate.Viable = false; 1990 return; 1991 } 1992 1993 // (C++ 13.3.2p2): A candidate function having more than m parameters 1994 // is viable only if the (m+1)st parameter has a default argument 1995 // (8.3.6). For the purposes of overload resolution, the 1996 // parameter list is truncated on the right, so that there are 1997 // exactly m parameters. 1998 unsigned MinRequiredArgs = Method->getMinRequiredArguments(); 1999 if (NumArgs < MinRequiredArgs) { 2000 // Not enough arguments. 2001 Candidate.Viable = false; 2002 return; 2003 } 2004 2005 Candidate.Viable = true; 2006 Candidate.Conversions.resize(NumArgs + 1); 2007 2008 if (Method->isStatic() || !Object) 2009 // The implicit object argument is ignored. 2010 Candidate.IgnoreObjectArgument = true; 2011 else { 2012 // Determine the implicit conversion sequence for the object 2013 // parameter. 2014 Candidate.Conversions[0] = TryObjectArgumentInitialization(Object, Method); 2015 if (Candidate.Conversions[0].ConversionKind 2016 == ImplicitConversionSequence::BadConversion) { 2017 Candidate.Viable = false; 2018 return; 2019 } 2020 } 2021 2022 // Determine the implicit conversion sequences for each of the 2023 // arguments. 2024 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2025 if (ArgIdx < NumArgsInProto) { 2026 // (C++ 13.3.2p3): for F to be a viable function, there shall 2027 // exist for each argument an implicit conversion sequence 2028 // (13.3.3.1) that converts that argument to the corresponding 2029 // parameter of F. 2030 QualType ParamType = Proto->getArgType(ArgIdx); 2031 Candidate.Conversions[ArgIdx + 1] 2032 = TryCopyInitialization(Args[ArgIdx], ParamType, 2033 SuppressUserConversions); 2034 if (Candidate.Conversions[ArgIdx + 1].ConversionKind 2035 == ImplicitConversionSequence::BadConversion) { 2036 Candidate.Viable = false; 2037 break; 2038 } 2039 } else { 2040 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2041 // argument for which there is no corresponding parameter is 2042 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2043 Candidate.Conversions[ArgIdx + 1].ConversionKind 2044 = ImplicitConversionSequence::EllipsisConversion; 2045 } 2046 } 2047} 2048 2049/// AddConversionCandidate - Add a C++ conversion function as a 2050/// candidate in the candidate set (C++ [over.match.conv], 2051/// C++ [over.match.copy]). From is the expression we're converting from, 2052/// and ToType is the type that we're eventually trying to convert to 2053/// (which may or may not be the same type as the type that the 2054/// conversion function produces). 2055void 2056Sema::AddConversionCandidate(CXXConversionDecl *Conversion, 2057 Expr *From, QualType ToType, 2058 OverloadCandidateSet& CandidateSet) { 2059 // Add this candidate 2060 CandidateSet.push_back(OverloadCandidate()); 2061 OverloadCandidate& Candidate = CandidateSet.back(); 2062 Candidate.Function = Conversion; 2063 Candidate.IsSurrogate = false; 2064 Candidate.IgnoreObjectArgument = false; 2065 Candidate.FinalConversion.setAsIdentityConversion(); 2066 Candidate.FinalConversion.FromTypePtr 2067 = Conversion->getConversionType().getAsOpaquePtr(); 2068 Candidate.FinalConversion.ToTypePtr = ToType.getAsOpaquePtr(); 2069 2070 // Determine the implicit conversion sequence for the implicit 2071 // object parameter. 2072 Candidate.Viable = true; 2073 Candidate.Conversions.resize(1); 2074 Candidate.Conversions[0] = TryObjectArgumentInitialization(From, Conversion); 2075 2076 if (Candidate.Conversions[0].ConversionKind 2077 == ImplicitConversionSequence::BadConversion) { 2078 Candidate.Viable = false; 2079 return; 2080 } 2081 2082 // To determine what the conversion from the result of calling the 2083 // conversion function to the type we're eventually trying to 2084 // convert to (ToType), we need to synthesize a call to the 2085 // conversion function and attempt copy initialization from it. This 2086 // makes sure that we get the right semantics with respect to 2087 // lvalues/rvalues and the type. Fortunately, we can allocate this 2088 // call on the stack and we don't need its arguments to be 2089 // well-formed. 2090 DeclRefExpr ConversionRef(Conversion, Conversion->getType(), 2091 SourceLocation()); 2092 ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()), 2093 &ConversionRef, false); 2094 CallExpr Call(&ConversionFn, 0, 0, 2095 Conversion->getConversionType().getNonReferenceType(), 2096 SourceLocation()); 2097 ImplicitConversionSequence ICS = TryCopyInitialization(&Call, ToType, true); 2098 switch (ICS.ConversionKind) { 2099 case ImplicitConversionSequence::StandardConversion: 2100 Candidate.FinalConversion = ICS.Standard; 2101 break; 2102 2103 case ImplicitConversionSequence::BadConversion: 2104 Candidate.Viable = false; 2105 break; 2106 2107 default: 2108 assert(false && 2109 "Can only end up with a standard conversion sequence or failure"); 2110 } 2111} 2112 2113/// AddSurrogateCandidate - Adds a "surrogate" candidate function that 2114/// converts the given @c Object to a function pointer via the 2115/// conversion function @c Conversion, and then attempts to call it 2116/// with the given arguments (C++ [over.call.object]p2-4). Proto is 2117/// the type of function that we'll eventually be calling. 2118void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, 2119 const FunctionTypeProto *Proto, 2120 Expr *Object, Expr **Args, unsigned NumArgs, 2121 OverloadCandidateSet& CandidateSet) { 2122 CandidateSet.push_back(OverloadCandidate()); 2123 OverloadCandidate& Candidate = CandidateSet.back(); 2124 Candidate.Function = 0; 2125 Candidate.Surrogate = Conversion; 2126 Candidate.Viable = true; 2127 Candidate.IsSurrogate = true; 2128 Candidate.IgnoreObjectArgument = false; 2129 Candidate.Conversions.resize(NumArgs + 1); 2130 2131 // Determine the implicit conversion sequence for the implicit 2132 // object parameter. 2133 ImplicitConversionSequence ObjectInit 2134 = TryObjectArgumentInitialization(Object, Conversion); 2135 if (ObjectInit.ConversionKind == ImplicitConversionSequence::BadConversion) { 2136 Candidate.Viable = false; 2137 return; 2138 } 2139 2140 // The first conversion is actually a user-defined conversion whose 2141 // first conversion is ObjectInit's standard conversion (which is 2142 // effectively a reference binding). Record it as such. 2143 Candidate.Conversions[0].ConversionKind 2144 = ImplicitConversionSequence::UserDefinedConversion; 2145 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; 2146 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; 2147 Candidate.Conversions[0].UserDefined.After 2148 = Candidate.Conversions[0].UserDefined.Before; 2149 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); 2150 2151 // Find the 2152 unsigned NumArgsInProto = Proto->getNumArgs(); 2153 2154 // (C++ 13.3.2p2): A candidate function having fewer than m 2155 // parameters is viable only if it has an ellipsis in its parameter 2156 // list (8.3.5). 2157 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2158 Candidate.Viable = false; 2159 return; 2160 } 2161 2162 // Function types don't have any default arguments, so just check if 2163 // we have enough arguments. 2164 if (NumArgs < NumArgsInProto) { 2165 // Not enough arguments. 2166 Candidate.Viable = false; 2167 return; 2168 } 2169 2170 // Determine the implicit conversion sequences for each of the 2171 // arguments. 2172 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2173 if (ArgIdx < NumArgsInProto) { 2174 // (C++ 13.3.2p3): for F to be a viable function, there shall 2175 // exist for each argument an implicit conversion sequence 2176 // (13.3.3.1) that converts that argument to the corresponding 2177 // parameter of F. 2178 QualType ParamType = Proto->getArgType(ArgIdx); 2179 Candidate.Conversions[ArgIdx + 1] 2180 = TryCopyInitialization(Args[ArgIdx], ParamType, 2181 /*SuppressUserConversions=*/false); 2182 if (Candidate.Conversions[ArgIdx + 1].ConversionKind 2183 == ImplicitConversionSequence::BadConversion) { 2184 Candidate.Viable = false; 2185 break; 2186 } 2187 } else { 2188 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2189 // argument for which there is no corresponding parameter is 2190 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2191 Candidate.Conversions[ArgIdx + 1].ConversionKind 2192 = ImplicitConversionSequence::EllipsisConversion; 2193 } 2194 } 2195} 2196 2197/// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is 2198/// an acceptable non-member overloaded operator for a call whose 2199/// arguments have types T1 (and, if non-empty, T2). This routine 2200/// implements the check in C++ [over.match.oper]p3b2 concerning 2201/// enumeration types. 2202static bool 2203IsAcceptableNonMemberOperatorCandidate(FunctionDecl *Fn, 2204 QualType T1, QualType T2, 2205 ASTContext &Context) { 2206 if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType())) 2207 return true; 2208 2209 const FunctionTypeProto *Proto = Fn->getType()->getAsFunctionTypeProto(); 2210 if (Proto->getNumArgs() < 1) 2211 return false; 2212 2213 if (T1->isEnumeralType()) { 2214 QualType ArgType = Proto->getArgType(0).getNonReferenceType(); 2215 if (Context.getCanonicalType(T1).getUnqualifiedType() 2216 == Context.getCanonicalType(ArgType).getUnqualifiedType()) 2217 return true; 2218 } 2219 2220 if (Proto->getNumArgs() < 2) 2221 return false; 2222 2223 if (!T2.isNull() && T2->isEnumeralType()) { 2224 QualType ArgType = Proto->getArgType(1).getNonReferenceType(); 2225 if (Context.getCanonicalType(T2).getUnqualifiedType() 2226 == Context.getCanonicalType(ArgType).getUnqualifiedType()) 2227 return true; 2228 } 2229 2230 return false; 2231} 2232 2233/// AddOperatorCandidates - Add the overloaded operator candidates for 2234/// the operator Op that was used in an operator expression such as "x 2235/// Op y". S is the scope in which the expression occurred (used for 2236/// name lookup of the operator), Args/NumArgs provides the operator 2237/// arguments, and CandidateSet will store the added overload 2238/// candidates. (C++ [over.match.oper]). 2239void Sema::AddOperatorCandidates(OverloadedOperatorKind Op, Scope *S, 2240 Expr **Args, unsigned NumArgs, 2241 OverloadCandidateSet& CandidateSet) { 2242 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 2243 2244 // C++ [over.match.oper]p3: 2245 // For a unary operator @ with an operand of a type whose 2246 // cv-unqualified version is T1, and for a binary operator @ with 2247 // a left operand of a type whose cv-unqualified version is T1 and 2248 // a right operand of a type whose cv-unqualified version is T2, 2249 // three sets of candidate functions, designated member 2250 // candidates, non-member candidates and built-in candidates, are 2251 // constructed as follows: 2252 QualType T1 = Args[0]->getType(); 2253 QualType T2; 2254 if (NumArgs > 1) 2255 T2 = Args[1]->getType(); 2256 2257 // -- If T1 is a class type, the set of member candidates is the 2258 // result of the qualified lookup of T1::operator@ 2259 // (13.3.1.1.1); otherwise, the set of member candidates is 2260 // empty. 2261 if (const RecordType *T1Rec = T1->getAsRecordType()) { 2262 DeclContext::lookup_const_iterator Oper, OperEnd; 2263 for (llvm::tie(Oper, OperEnd) = T1Rec->getDecl()->lookup(OpName); 2264 Oper != OperEnd; ++Oper) 2265 AddMethodCandidate(cast<CXXMethodDecl>(*Oper), Args[0], 2266 Args+1, NumArgs - 1, CandidateSet, 2267 /*SuppressUserConversions=*/false); 2268 } 2269 2270 // -- The set of non-member candidates is the result of the 2271 // unqualified lookup of operator@ in the context of the 2272 // expression according to the usual rules for name lookup in 2273 // unqualified function calls (3.4.2) except that all member 2274 // functions are ignored. However, if no operand has a class 2275 // type, only those non-member functions in the lookup set 2276 // that have a first parameter of type T1 or “reference to 2277 // (possibly cv-qualified) T1”, when T1 is an enumeration 2278 // type, or (if there is a right operand) a second parameter 2279 // of type T2 or “reference to (possibly cv-qualified) T2”, 2280 // when T2 is an enumeration type, are candidate functions. 2281 { 2282 IdentifierResolver::iterator I = IdResolver.begin(OpName), 2283 IEnd = IdResolver.end(); 2284 for (; I != IEnd; ++I) { 2285 // We don't need to check the identifier namespace, because 2286 // operator names can only be ordinary identifiers. 2287 2288 // Ignore member functions. 2289 if ((*I)->getDeclContext()->isRecord()) 2290 continue; 2291 2292 // We found something with this name. We're done. 2293 break; 2294 } 2295 2296 if (I != IEnd) { 2297 Decl *FirstDecl = *I; 2298 for (; I != IEnd; ++I) { 2299 if (FirstDecl->getDeclContext() != (*I)->getDeclContext()) 2300 break; 2301 2302 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) 2303 if (IsAcceptableNonMemberOperatorCandidate(FD, T1, T2, Context)) 2304 AddOverloadCandidate(FD, Args, NumArgs, CandidateSet, 2305 /*SuppressUserConversions=*/false); 2306 } 2307 } 2308 } 2309 2310 // Add builtin overload candidates (C++ [over.built]). 2311 AddBuiltinOperatorCandidates(Op, Args, NumArgs, CandidateSet); 2312} 2313 2314/// AddBuiltinCandidate - Add a candidate for a built-in 2315/// operator. ResultTy and ParamTys are the result and parameter types 2316/// of the built-in candidate, respectively. Args and NumArgs are the 2317/// arguments being passed to the candidate. IsAssignmentOperator 2318/// should be true when this built-in candidate is an assignment 2319/// operator. NumContextualBoolArguments is the number of arguments 2320/// (at the beginning of the argument list) that will be contextually 2321/// converted to bool. 2322void Sema::AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys, 2323 Expr **Args, unsigned NumArgs, 2324 OverloadCandidateSet& CandidateSet, 2325 bool IsAssignmentOperator, 2326 unsigned NumContextualBoolArguments) { 2327 // Add this candidate 2328 CandidateSet.push_back(OverloadCandidate()); 2329 OverloadCandidate& Candidate = CandidateSet.back(); 2330 Candidate.Function = 0; 2331 Candidate.IsSurrogate = false; 2332 Candidate.IgnoreObjectArgument = false; 2333 Candidate.BuiltinTypes.ResultTy = ResultTy; 2334 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 2335 Candidate.BuiltinTypes.ParamTypes[ArgIdx] = ParamTys[ArgIdx]; 2336 2337 // Determine the implicit conversion sequences for each of the 2338 // arguments. 2339 Candidate.Viable = true; 2340 Candidate.Conversions.resize(NumArgs); 2341 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2342 // C++ [over.match.oper]p4: 2343 // For the built-in assignment operators, conversions of the 2344 // left operand are restricted as follows: 2345 // -- no temporaries are introduced to hold the left operand, and 2346 // -- no user-defined conversions are applied to the left 2347 // operand to achieve a type match with the left-most 2348 // parameter of a built-in candidate. 2349 // 2350 // We block these conversions by turning off user-defined 2351 // conversions, since that is the only way that initialization of 2352 // a reference to a non-class type can occur from something that 2353 // is not of the same type. 2354 if (ArgIdx < NumContextualBoolArguments) { 2355 assert(ParamTys[ArgIdx] == Context.BoolTy && 2356 "Contextual conversion to bool requires bool type"); 2357 Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(Args[ArgIdx]); 2358 } else { 2359 Candidate.Conversions[ArgIdx] 2360 = TryCopyInitialization(Args[ArgIdx], ParamTys[ArgIdx], 2361 ArgIdx == 0 && IsAssignmentOperator); 2362 } 2363 if (Candidate.Conversions[ArgIdx].ConversionKind 2364 == ImplicitConversionSequence::BadConversion) { 2365 Candidate.Viable = false; 2366 break; 2367 } 2368 } 2369} 2370 2371/// BuiltinCandidateTypeSet - A set of types that will be used for the 2372/// candidate operator functions for built-in operators (C++ 2373/// [over.built]). The types are separated into pointer types and 2374/// enumeration types. 2375class BuiltinCandidateTypeSet { 2376 /// TypeSet - A set of types. 2377 typedef llvm::SmallPtrSet<void*, 8> TypeSet; 2378 2379 /// PointerTypes - The set of pointer types that will be used in the 2380 /// built-in candidates. 2381 TypeSet PointerTypes; 2382 2383 /// EnumerationTypes - The set of enumeration types that will be 2384 /// used in the built-in candidates. 2385 TypeSet EnumerationTypes; 2386 2387 /// Context - The AST context in which we will build the type sets. 2388 ASTContext &Context; 2389 2390 bool AddWithMoreQualifiedTypeVariants(QualType Ty); 2391 2392public: 2393 /// iterator - Iterates through the types that are part of the set. 2394 class iterator { 2395 TypeSet::iterator Base; 2396 2397 public: 2398 typedef QualType value_type; 2399 typedef QualType reference; 2400 typedef QualType pointer; 2401 typedef std::ptrdiff_t difference_type; 2402 typedef std::input_iterator_tag iterator_category; 2403 2404 iterator(TypeSet::iterator B) : Base(B) { } 2405 2406 iterator& operator++() { 2407 ++Base; 2408 return *this; 2409 } 2410 2411 iterator operator++(int) { 2412 iterator tmp(*this); 2413 ++(*this); 2414 return tmp; 2415 } 2416 2417 reference operator*() const { 2418 return QualType::getFromOpaquePtr(*Base); 2419 } 2420 2421 pointer operator->() const { 2422 return **this; 2423 } 2424 2425 friend bool operator==(iterator LHS, iterator RHS) { 2426 return LHS.Base == RHS.Base; 2427 } 2428 2429 friend bool operator!=(iterator LHS, iterator RHS) { 2430 return LHS.Base != RHS.Base; 2431 } 2432 }; 2433 2434 BuiltinCandidateTypeSet(ASTContext &Context) : Context(Context) { } 2435 2436 void AddTypesConvertedFrom(QualType Ty, bool AllowUserConversions, 2437 bool AllowExplicitConversions); 2438 2439 /// pointer_begin - First pointer type found; 2440 iterator pointer_begin() { return PointerTypes.begin(); } 2441 2442 /// pointer_end - Last pointer type found; 2443 iterator pointer_end() { return PointerTypes.end(); } 2444 2445 /// enumeration_begin - First enumeration type found; 2446 iterator enumeration_begin() { return EnumerationTypes.begin(); } 2447 2448 /// enumeration_end - Last enumeration type found; 2449 iterator enumeration_end() { return EnumerationTypes.end(); } 2450}; 2451 2452/// AddWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to 2453/// the set of pointer types along with any more-qualified variants of 2454/// that type. For example, if @p Ty is "int const *", this routine 2455/// will add "int const *", "int const volatile *", "int const 2456/// restrict *", and "int const volatile restrict *" to the set of 2457/// pointer types. Returns true if the add of @p Ty itself succeeded, 2458/// false otherwise. 2459bool BuiltinCandidateTypeSet::AddWithMoreQualifiedTypeVariants(QualType Ty) { 2460 // Insert this type. 2461 if (!PointerTypes.insert(Ty.getAsOpaquePtr())) 2462 return false; 2463 2464 if (const PointerType *PointerTy = Ty->getAsPointerType()) { 2465 QualType PointeeTy = PointerTy->getPointeeType(); 2466 // FIXME: Optimize this so that we don't keep trying to add the same types. 2467 2468 // FIXME: Do we have to add CVR qualifiers at *all* levels to deal 2469 // with all pointer conversions that don't cast away constness? 2470 if (!PointeeTy.isConstQualified()) 2471 AddWithMoreQualifiedTypeVariants 2472 (Context.getPointerType(PointeeTy.withConst())); 2473 if (!PointeeTy.isVolatileQualified()) 2474 AddWithMoreQualifiedTypeVariants 2475 (Context.getPointerType(PointeeTy.withVolatile())); 2476 if (!PointeeTy.isRestrictQualified()) 2477 AddWithMoreQualifiedTypeVariants 2478 (Context.getPointerType(PointeeTy.withRestrict())); 2479 } 2480 2481 return true; 2482} 2483 2484/// AddTypesConvertedFrom - Add each of the types to which the type @p 2485/// Ty can be implicit converted to the given set of @p Types. We're 2486/// primarily interested in pointer types and enumeration types. 2487/// AllowUserConversions is true if we should look at the conversion 2488/// functions of a class type, and AllowExplicitConversions if we 2489/// should also include the explicit conversion functions of a class 2490/// type. 2491void 2492BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, 2493 bool AllowUserConversions, 2494 bool AllowExplicitConversions) { 2495 // Only deal with canonical types. 2496 Ty = Context.getCanonicalType(Ty); 2497 2498 // Look through reference types; they aren't part of the type of an 2499 // expression for the purposes of conversions. 2500 if (const ReferenceType *RefTy = Ty->getAsReferenceType()) 2501 Ty = RefTy->getPointeeType(); 2502 2503 // We don't care about qualifiers on the type. 2504 Ty = Ty.getUnqualifiedType(); 2505 2506 if (const PointerType *PointerTy = Ty->getAsPointerType()) { 2507 QualType PointeeTy = PointerTy->getPointeeType(); 2508 2509 // Insert our type, and its more-qualified variants, into the set 2510 // of types. 2511 if (!AddWithMoreQualifiedTypeVariants(Ty)) 2512 return; 2513 2514 // Add 'cv void*' to our set of types. 2515 if (!Ty->isVoidType()) { 2516 QualType QualVoid 2517 = Context.VoidTy.getQualifiedType(PointeeTy.getCVRQualifiers()); 2518 AddWithMoreQualifiedTypeVariants(Context.getPointerType(QualVoid)); 2519 } 2520 2521 // If this is a pointer to a class type, add pointers to its bases 2522 // (with the same level of cv-qualification as the original 2523 // derived class, of course). 2524 if (const RecordType *PointeeRec = PointeeTy->getAsRecordType()) { 2525 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(PointeeRec->getDecl()); 2526 for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin(); 2527 Base != ClassDecl->bases_end(); ++Base) { 2528 QualType BaseTy = Context.getCanonicalType(Base->getType()); 2529 BaseTy = BaseTy.getQualifiedType(PointeeTy.getCVRQualifiers()); 2530 2531 // Add the pointer type, recursively, so that we get all of 2532 // the indirect base classes, too. 2533 AddTypesConvertedFrom(Context.getPointerType(BaseTy), false, false); 2534 } 2535 } 2536 } else if (Ty->isEnumeralType()) { 2537 EnumerationTypes.insert(Ty.getAsOpaquePtr()); 2538 } else if (AllowUserConversions) { 2539 if (const RecordType *TyRec = Ty->getAsRecordType()) { 2540 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 2541 // FIXME: Visit conversion functions in the base classes, too. 2542 OverloadedFunctionDecl *Conversions 2543 = ClassDecl->getConversionFunctions(); 2544 for (OverloadedFunctionDecl::function_iterator Func 2545 = Conversions->function_begin(); 2546 Func != Conversions->function_end(); ++Func) { 2547 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func); 2548 if (AllowExplicitConversions || !Conv->isExplicit()) 2549 AddTypesConvertedFrom(Conv->getConversionType(), false, false); 2550 } 2551 } 2552 } 2553} 2554 2555/// AddBuiltinOperatorCandidates - Add the appropriate built-in 2556/// operator overloads to the candidate set (C++ [over.built]), based 2557/// on the operator @p Op and the arguments given. For example, if the 2558/// operator is a binary '+', this routine might add "int 2559/// operator+(int, int)" to cover integer addition. 2560void 2561Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, 2562 Expr **Args, unsigned NumArgs, 2563 OverloadCandidateSet& CandidateSet) { 2564 // The set of "promoted arithmetic types", which are the arithmetic 2565 // types are that preserved by promotion (C++ [over.built]p2). Note 2566 // that the first few of these types are the promoted integral 2567 // types; these types need to be first. 2568 // FIXME: What about complex? 2569 const unsigned FirstIntegralType = 0; 2570 const unsigned LastIntegralType = 13; 2571 const unsigned FirstPromotedIntegralType = 7, 2572 LastPromotedIntegralType = 13; 2573 const unsigned FirstPromotedArithmeticType = 7, 2574 LastPromotedArithmeticType = 16; 2575 const unsigned NumArithmeticTypes = 16; 2576 QualType ArithmeticTypes[NumArithmeticTypes] = { 2577 Context.BoolTy, Context.CharTy, Context.WCharTy, 2578 Context.SignedCharTy, Context.ShortTy, 2579 Context.UnsignedCharTy, Context.UnsignedShortTy, 2580 Context.IntTy, Context.LongTy, Context.LongLongTy, 2581 Context.UnsignedIntTy, Context.UnsignedLongTy, Context.UnsignedLongLongTy, 2582 Context.FloatTy, Context.DoubleTy, Context.LongDoubleTy 2583 }; 2584 2585 // Find all of the types that the arguments can convert to, but only 2586 // if the operator we're looking at has built-in operator candidates 2587 // that make use of these types. 2588 BuiltinCandidateTypeSet CandidateTypes(Context); 2589 if (Op == OO_Less || Op == OO_Greater || Op == OO_LessEqual || 2590 Op == OO_GreaterEqual || Op == OO_EqualEqual || Op == OO_ExclaimEqual || 2591 Op == OO_Plus || (Op == OO_Minus && NumArgs == 2) || Op == OO_Equal || 2592 Op == OO_PlusEqual || Op == OO_MinusEqual || Op == OO_Subscript || 2593 Op == OO_ArrowStar || Op == OO_PlusPlus || Op == OO_MinusMinus || 2594 (Op == OO_Star && NumArgs == 1)) { 2595 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 2596 CandidateTypes.AddTypesConvertedFrom(Args[ArgIdx]->getType(), 2597 true, 2598 (Op == OO_Exclaim || 2599 Op == OO_AmpAmp || 2600 Op == OO_PipePipe)); 2601 } 2602 2603 bool isComparison = false; 2604 switch (Op) { 2605 case OO_None: 2606 case NUM_OVERLOADED_OPERATORS: 2607 assert(false && "Expected an overloaded operator"); 2608 break; 2609 2610 case OO_Star: // '*' is either unary or binary 2611 if (NumArgs == 1) 2612 goto UnaryStar; 2613 else 2614 goto BinaryStar; 2615 break; 2616 2617 case OO_Plus: // '+' is either unary or binary 2618 if (NumArgs == 1) 2619 goto UnaryPlus; 2620 else 2621 goto BinaryPlus; 2622 break; 2623 2624 case OO_Minus: // '-' is either unary or binary 2625 if (NumArgs == 1) 2626 goto UnaryMinus; 2627 else 2628 goto BinaryMinus; 2629 break; 2630 2631 case OO_Amp: // '&' is either unary or binary 2632 if (NumArgs == 1) 2633 goto UnaryAmp; 2634 else 2635 goto BinaryAmp; 2636 2637 case OO_PlusPlus: 2638 case OO_MinusMinus: 2639 // C++ [over.built]p3: 2640 // 2641 // For every pair (T, VQ), where T is an arithmetic type, and VQ 2642 // is either volatile or empty, there exist candidate operator 2643 // functions of the form 2644 // 2645 // VQ T& operator++(VQ T&); 2646 // T operator++(VQ T&, int); 2647 // 2648 // C++ [over.built]p4: 2649 // 2650 // For every pair (T, VQ), where T is an arithmetic type other 2651 // than bool, and VQ is either volatile or empty, there exist 2652 // candidate operator functions of the form 2653 // 2654 // VQ T& operator--(VQ T&); 2655 // T operator--(VQ T&, int); 2656 for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1); 2657 Arith < NumArithmeticTypes; ++Arith) { 2658 QualType ArithTy = ArithmeticTypes[Arith]; 2659 QualType ParamTypes[2] 2660 = { Context.getReferenceType(ArithTy), Context.IntTy }; 2661 2662 // Non-volatile version. 2663 if (NumArgs == 1) 2664 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2665 else 2666 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 2667 2668 // Volatile version 2669 ParamTypes[0] = Context.getReferenceType(ArithTy.withVolatile()); 2670 if (NumArgs == 1) 2671 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2672 else 2673 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 2674 } 2675 2676 // C++ [over.built]p5: 2677 // 2678 // For every pair (T, VQ), where T is a cv-qualified or 2679 // cv-unqualified object type, and VQ is either volatile or 2680 // empty, there exist candidate operator functions of the form 2681 // 2682 // T*VQ& operator++(T*VQ&); 2683 // T*VQ& operator--(T*VQ&); 2684 // T* operator++(T*VQ&, int); 2685 // T* operator--(T*VQ&, int); 2686 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2687 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2688 // Skip pointer types that aren't pointers to object types. 2689 if (!(*Ptr)->getAsPointerType()->getPointeeType()->isIncompleteOrObjectType()) 2690 continue; 2691 2692 QualType ParamTypes[2] = { 2693 Context.getReferenceType(*Ptr), Context.IntTy 2694 }; 2695 2696 // Without volatile 2697 if (NumArgs == 1) 2698 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2699 else 2700 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2701 2702 if (!Context.getCanonicalType(*Ptr).isVolatileQualified()) { 2703 // With volatile 2704 ParamTypes[0] = Context.getReferenceType((*Ptr).withVolatile()); 2705 if (NumArgs == 1) 2706 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2707 else 2708 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2709 } 2710 } 2711 break; 2712 2713 UnaryStar: 2714 // C++ [over.built]p6: 2715 // For every cv-qualified or cv-unqualified object type T, there 2716 // exist candidate operator functions of the form 2717 // 2718 // T& operator*(T*); 2719 // 2720 // C++ [over.built]p7: 2721 // For every function type T, there exist candidate operator 2722 // functions of the form 2723 // T& operator*(T*); 2724 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2725 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2726 QualType ParamTy = *Ptr; 2727 QualType PointeeTy = ParamTy->getAsPointerType()->getPointeeType(); 2728 AddBuiltinCandidate(Context.getReferenceType(PointeeTy), 2729 &ParamTy, Args, 1, CandidateSet); 2730 } 2731 break; 2732 2733 UnaryPlus: 2734 // C++ [over.built]p8: 2735 // For every type T, there exist candidate operator functions of 2736 // the form 2737 // 2738 // T* operator+(T*); 2739 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2740 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2741 QualType ParamTy = *Ptr; 2742 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet); 2743 } 2744 2745 // Fall through 2746 2747 UnaryMinus: 2748 // C++ [over.built]p9: 2749 // For every promoted arithmetic type T, there exist candidate 2750 // operator functions of the form 2751 // 2752 // T operator+(T); 2753 // T operator-(T); 2754 for (unsigned Arith = FirstPromotedArithmeticType; 2755 Arith < LastPromotedArithmeticType; ++Arith) { 2756 QualType ArithTy = ArithmeticTypes[Arith]; 2757 AddBuiltinCandidate(ArithTy, &ArithTy, Args, 1, CandidateSet); 2758 } 2759 break; 2760 2761 case OO_Tilde: 2762 // C++ [over.built]p10: 2763 // For every promoted integral type T, there exist candidate 2764 // operator functions of the form 2765 // 2766 // T operator~(T); 2767 for (unsigned Int = FirstPromotedIntegralType; 2768 Int < LastPromotedIntegralType; ++Int) { 2769 QualType IntTy = ArithmeticTypes[Int]; 2770 AddBuiltinCandidate(IntTy, &IntTy, Args, 1, CandidateSet); 2771 } 2772 break; 2773 2774 case OO_New: 2775 case OO_Delete: 2776 case OO_Array_New: 2777 case OO_Array_Delete: 2778 case OO_Call: 2779 assert(false && "Special operators don't use AddBuiltinOperatorCandidates"); 2780 break; 2781 2782 case OO_Comma: 2783 UnaryAmp: 2784 case OO_Arrow: 2785 // C++ [over.match.oper]p3: 2786 // -- For the operator ',', the unary operator '&', or the 2787 // operator '->', the built-in candidates set is empty. 2788 break; 2789 2790 case OO_Less: 2791 case OO_Greater: 2792 case OO_LessEqual: 2793 case OO_GreaterEqual: 2794 case OO_EqualEqual: 2795 case OO_ExclaimEqual: 2796 // C++ [over.built]p15: 2797 // 2798 // For every pointer or enumeration type T, there exist 2799 // candidate operator functions of the form 2800 // 2801 // bool operator<(T, T); 2802 // bool operator>(T, T); 2803 // bool operator<=(T, T); 2804 // bool operator>=(T, T); 2805 // bool operator==(T, T); 2806 // bool operator!=(T, T); 2807 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2808 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2809 QualType ParamTypes[2] = { *Ptr, *Ptr }; 2810 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 2811 } 2812 for (BuiltinCandidateTypeSet::iterator Enum 2813 = CandidateTypes.enumeration_begin(); 2814 Enum != CandidateTypes.enumeration_end(); ++Enum) { 2815 QualType ParamTypes[2] = { *Enum, *Enum }; 2816 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 2817 } 2818 2819 // Fall through. 2820 isComparison = true; 2821 2822 BinaryPlus: 2823 BinaryMinus: 2824 if (!isComparison) { 2825 // We didn't fall through, so we must have OO_Plus or OO_Minus. 2826 2827 // C++ [over.built]p13: 2828 // 2829 // For every cv-qualified or cv-unqualified object type T 2830 // there exist candidate operator functions of the form 2831 // 2832 // T* operator+(T*, ptrdiff_t); 2833 // T& operator[](T*, ptrdiff_t); [BELOW] 2834 // T* operator-(T*, ptrdiff_t); 2835 // T* operator+(ptrdiff_t, T*); 2836 // T& operator[](ptrdiff_t, T*); [BELOW] 2837 // 2838 // C++ [over.built]p14: 2839 // 2840 // For every T, where T is a pointer to object type, there 2841 // exist candidate operator functions of the form 2842 // 2843 // ptrdiff_t operator-(T, T); 2844 for (BuiltinCandidateTypeSet::iterator Ptr 2845 = CandidateTypes.pointer_begin(); 2846 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2847 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 2848 2849 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) 2850 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2851 2852 if (Op == OO_Plus) { 2853 // T* operator+(ptrdiff_t, T*); 2854 ParamTypes[0] = ParamTypes[1]; 2855 ParamTypes[1] = *Ptr; 2856 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2857 } else { 2858 // ptrdiff_t operator-(T, T); 2859 ParamTypes[1] = *Ptr; 2860 AddBuiltinCandidate(Context.getPointerDiffType(), ParamTypes, 2861 Args, 2, CandidateSet); 2862 } 2863 } 2864 } 2865 // Fall through 2866 2867 case OO_Slash: 2868 BinaryStar: 2869 // C++ [over.built]p12: 2870 // 2871 // For every pair of promoted arithmetic types L and R, there 2872 // exist candidate operator functions of the form 2873 // 2874 // LR operator*(L, R); 2875 // LR operator/(L, R); 2876 // LR operator+(L, R); 2877 // LR operator-(L, R); 2878 // bool operator<(L, R); 2879 // bool operator>(L, R); 2880 // bool operator<=(L, R); 2881 // bool operator>=(L, R); 2882 // bool operator==(L, R); 2883 // bool operator!=(L, R); 2884 // 2885 // where LR is the result of the usual arithmetic conversions 2886 // between types L and R. 2887 for (unsigned Left = FirstPromotedArithmeticType; 2888 Left < LastPromotedArithmeticType; ++Left) { 2889 for (unsigned Right = FirstPromotedArithmeticType; 2890 Right < LastPromotedArithmeticType; ++Right) { 2891 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 2892 QualType Result 2893 = isComparison? Context.BoolTy 2894 : UsualArithmeticConversionsType(LandR[0], LandR[1]); 2895 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 2896 } 2897 } 2898 break; 2899 2900 case OO_Percent: 2901 BinaryAmp: 2902 case OO_Caret: 2903 case OO_Pipe: 2904 case OO_LessLess: 2905 case OO_GreaterGreater: 2906 // C++ [over.built]p17: 2907 // 2908 // For every pair of promoted integral types L and R, there 2909 // exist candidate operator functions of the form 2910 // 2911 // LR operator%(L, R); 2912 // LR operator&(L, R); 2913 // LR operator^(L, R); 2914 // LR operator|(L, R); 2915 // L operator<<(L, R); 2916 // L operator>>(L, R); 2917 // 2918 // where LR is the result of the usual arithmetic conversions 2919 // between types L and R. 2920 for (unsigned Left = FirstPromotedIntegralType; 2921 Left < LastPromotedIntegralType; ++Left) { 2922 for (unsigned Right = FirstPromotedIntegralType; 2923 Right < LastPromotedIntegralType; ++Right) { 2924 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 2925 QualType Result = (Op == OO_LessLess || Op == OO_GreaterGreater) 2926 ? LandR[0] 2927 : UsualArithmeticConversionsType(LandR[0], LandR[1]); 2928 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 2929 } 2930 } 2931 break; 2932 2933 case OO_Equal: 2934 // C++ [over.built]p20: 2935 // 2936 // For every pair (T, VQ), where T is an enumeration or 2937 // (FIXME:) pointer to member type and VQ is either volatile or 2938 // empty, there exist candidate operator functions of the form 2939 // 2940 // VQ T& operator=(VQ T&, T); 2941 for (BuiltinCandidateTypeSet::iterator Enum 2942 = CandidateTypes.enumeration_begin(); 2943 Enum != CandidateTypes.enumeration_end(); ++Enum) { 2944 QualType ParamTypes[2]; 2945 2946 // T& operator=(T&, T) 2947 ParamTypes[0] = Context.getReferenceType(*Enum); 2948 ParamTypes[1] = *Enum; 2949 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 2950 /*IsAssignmentOperator=*/false); 2951 2952 if (!Context.getCanonicalType(*Enum).isVolatileQualified()) { 2953 // volatile T& operator=(volatile T&, T) 2954 ParamTypes[0] = Context.getReferenceType((*Enum).withVolatile()); 2955 ParamTypes[1] = *Enum; 2956 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 2957 /*IsAssignmentOperator=*/false); 2958 } 2959 } 2960 // Fall through. 2961 2962 case OO_PlusEqual: 2963 case OO_MinusEqual: 2964 // C++ [over.built]p19: 2965 // 2966 // For every pair (T, VQ), where T is any type and VQ is either 2967 // volatile or empty, there exist candidate operator functions 2968 // of the form 2969 // 2970 // T*VQ& operator=(T*VQ&, T*); 2971 // 2972 // C++ [over.built]p21: 2973 // 2974 // For every pair (T, VQ), where T is a cv-qualified or 2975 // cv-unqualified object type and VQ is either volatile or 2976 // empty, there exist candidate operator functions of the form 2977 // 2978 // T*VQ& operator+=(T*VQ&, ptrdiff_t); 2979 // T*VQ& operator-=(T*VQ&, ptrdiff_t); 2980 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2981 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2982 QualType ParamTypes[2]; 2983 ParamTypes[1] = (Op == OO_Equal)? *Ptr : Context.getPointerDiffType(); 2984 2985 // non-volatile version 2986 ParamTypes[0] = Context.getReferenceType(*Ptr); 2987 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 2988 /*IsAssigmentOperator=*/Op == OO_Equal); 2989 2990 if (!Context.getCanonicalType(*Ptr).isVolatileQualified()) { 2991 // volatile version 2992 ParamTypes[0] = Context.getReferenceType((*Ptr).withVolatile()); 2993 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 2994 /*IsAssigmentOperator=*/Op == OO_Equal); 2995 } 2996 } 2997 // Fall through. 2998 2999 case OO_StarEqual: 3000 case OO_SlashEqual: 3001 // C++ [over.built]p18: 3002 // 3003 // For every triple (L, VQ, R), where L is an arithmetic type, 3004 // VQ is either volatile or empty, and R is a promoted 3005 // arithmetic type, there exist candidate operator functions of 3006 // the form 3007 // 3008 // VQ L& operator=(VQ L&, R); 3009 // VQ L& operator*=(VQ L&, R); 3010 // VQ L& operator/=(VQ L&, R); 3011 // VQ L& operator+=(VQ L&, R); 3012 // VQ L& operator-=(VQ L&, R); 3013 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { 3014 for (unsigned Right = FirstPromotedArithmeticType; 3015 Right < LastPromotedArithmeticType; ++Right) { 3016 QualType ParamTypes[2]; 3017 ParamTypes[1] = ArithmeticTypes[Right]; 3018 3019 // Add this built-in operator as a candidate (VQ is empty). 3020 ParamTypes[0] = Context.getReferenceType(ArithmeticTypes[Left]); 3021 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3022 /*IsAssigmentOperator=*/Op == OO_Equal); 3023 3024 // Add this built-in operator as a candidate (VQ is 'volatile'). 3025 ParamTypes[0] = ArithmeticTypes[Left].withVolatile(); 3026 ParamTypes[0] = Context.getReferenceType(ParamTypes[0]); 3027 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3028 /*IsAssigmentOperator=*/Op == OO_Equal); 3029 } 3030 } 3031 break; 3032 3033 case OO_PercentEqual: 3034 case OO_LessLessEqual: 3035 case OO_GreaterGreaterEqual: 3036 case OO_AmpEqual: 3037 case OO_CaretEqual: 3038 case OO_PipeEqual: 3039 // C++ [over.built]p22: 3040 // 3041 // For every triple (L, VQ, R), where L is an integral type, VQ 3042 // is either volatile or empty, and R is a promoted integral 3043 // type, there exist candidate operator functions of the form 3044 // 3045 // VQ L& operator%=(VQ L&, R); 3046 // VQ L& operator<<=(VQ L&, R); 3047 // VQ L& operator>>=(VQ L&, R); 3048 // VQ L& operator&=(VQ L&, R); 3049 // VQ L& operator^=(VQ L&, R); 3050 // VQ L& operator|=(VQ L&, R); 3051 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { 3052 for (unsigned Right = FirstPromotedIntegralType; 3053 Right < LastPromotedIntegralType; ++Right) { 3054 QualType ParamTypes[2]; 3055 ParamTypes[1] = ArithmeticTypes[Right]; 3056 3057 // Add this built-in operator as a candidate (VQ is empty). 3058 ParamTypes[0] = Context.getReferenceType(ArithmeticTypes[Left]); 3059 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 3060 3061 // Add this built-in operator as a candidate (VQ is 'volatile'). 3062 ParamTypes[0] = ArithmeticTypes[Left]; 3063 ParamTypes[0].addVolatile(); 3064 ParamTypes[0] = Context.getReferenceType(ParamTypes[0]); 3065 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 3066 } 3067 } 3068 break; 3069 3070 case OO_Exclaim: { 3071 // C++ [over.operator]p23: 3072 // 3073 // There also exist candidate operator functions of the form 3074 // 3075 // bool operator!(bool); 3076 // bool operator&&(bool, bool); [BELOW] 3077 // bool operator||(bool, bool); [BELOW] 3078 QualType ParamTy = Context.BoolTy; 3079 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet, 3080 /*IsAssignmentOperator=*/false, 3081 /*NumContextualBoolArguments=*/1); 3082 break; 3083 } 3084 3085 case OO_AmpAmp: 3086 case OO_PipePipe: { 3087 // C++ [over.operator]p23: 3088 // 3089 // There also exist candidate operator functions of the form 3090 // 3091 // bool operator!(bool); [ABOVE] 3092 // bool operator&&(bool, bool); 3093 // bool operator||(bool, bool); 3094 QualType ParamTypes[2] = { Context.BoolTy, Context.BoolTy }; 3095 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet, 3096 /*IsAssignmentOperator=*/false, 3097 /*NumContextualBoolArguments=*/2); 3098 break; 3099 } 3100 3101 case OO_Subscript: 3102 // C++ [over.built]p13: 3103 // 3104 // For every cv-qualified or cv-unqualified object type T there 3105 // exist candidate operator functions of the form 3106 // 3107 // T* operator+(T*, ptrdiff_t); [ABOVE] 3108 // T& operator[](T*, ptrdiff_t); 3109 // T* operator-(T*, ptrdiff_t); [ABOVE] 3110 // T* operator+(ptrdiff_t, T*); [ABOVE] 3111 // T& operator[](ptrdiff_t, T*); 3112 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3113 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3114 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 3115 QualType PointeeType = (*Ptr)->getAsPointerType()->getPointeeType(); 3116 QualType ResultTy = Context.getReferenceType(PointeeType); 3117 3118 // T& operator[](T*, ptrdiff_t) 3119 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 3120 3121 // T& operator[](ptrdiff_t, T*); 3122 ParamTypes[0] = ParamTypes[1]; 3123 ParamTypes[1] = *Ptr; 3124 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 3125 } 3126 break; 3127 3128 case OO_ArrowStar: 3129 // FIXME: No support for pointer-to-members yet. 3130 break; 3131 } 3132} 3133 3134/// AddOverloadCandidates - Add all of the function overloads in Ovl 3135/// to the candidate set. 3136void 3137Sema::AddOverloadCandidates(const OverloadedFunctionDecl *Ovl, 3138 Expr **Args, unsigned NumArgs, 3139 OverloadCandidateSet& CandidateSet, 3140 bool SuppressUserConversions) 3141{ 3142 for (OverloadedFunctionDecl::function_const_iterator Func 3143 = Ovl->function_begin(); 3144 Func != Ovl->function_end(); ++Func) 3145 AddOverloadCandidate(*Func, Args, NumArgs, CandidateSet, 3146 SuppressUserConversions); 3147} 3148 3149/// isBetterOverloadCandidate - Determines whether the first overload 3150/// candidate is a better candidate than the second (C++ 13.3.3p1). 3151bool 3152Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1, 3153 const OverloadCandidate& Cand2) 3154{ 3155 // Define viable functions to be better candidates than non-viable 3156 // functions. 3157 if (!Cand2.Viable) 3158 return Cand1.Viable; 3159 else if (!Cand1.Viable) 3160 return false; 3161 3162 // C++ [over.match.best]p1: 3163 // 3164 // -- if F is a static member function, ICS1(F) is defined such 3165 // that ICS1(F) is neither better nor worse than ICS1(G) for 3166 // any function G, and, symmetrically, ICS1(G) is neither 3167 // better nor worse than ICS1(F). 3168 unsigned StartArg = 0; 3169 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) 3170 StartArg = 1; 3171 3172 // (C++ 13.3.3p1): a viable function F1 is defined to be a better 3173 // function than another viable function F2 if for all arguments i, 3174 // ICSi(F1) is not a worse conversion sequence than ICSi(F2), and 3175 // then... 3176 unsigned NumArgs = Cand1.Conversions.size(); 3177 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); 3178 bool HasBetterConversion = false; 3179 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { 3180 switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx], 3181 Cand2.Conversions[ArgIdx])) { 3182 case ImplicitConversionSequence::Better: 3183 // Cand1 has a better conversion sequence. 3184 HasBetterConversion = true; 3185 break; 3186 3187 case ImplicitConversionSequence::Worse: 3188 // Cand1 can't be better than Cand2. 3189 return false; 3190 3191 case ImplicitConversionSequence::Indistinguishable: 3192 // Do nothing. 3193 break; 3194 } 3195 } 3196 3197 if (HasBetterConversion) 3198 return true; 3199 3200 // FIXME: Several other bullets in (C++ 13.3.3p1) need to be 3201 // implemented, but they require template support. 3202 3203 // C++ [over.match.best]p1b4: 3204 // 3205 // -- the context is an initialization by user-defined conversion 3206 // (see 8.5, 13.3.1.5) and the standard conversion sequence 3207 // from the return type of F1 to the destination type (i.e., 3208 // the type of the entity being initialized) is a better 3209 // conversion sequence than the standard conversion sequence 3210 // from the return type of F2 to the destination type. 3211 if (Cand1.Function && Cand2.Function && 3212 isa<CXXConversionDecl>(Cand1.Function) && 3213 isa<CXXConversionDecl>(Cand2.Function)) { 3214 switch (CompareStandardConversionSequences(Cand1.FinalConversion, 3215 Cand2.FinalConversion)) { 3216 case ImplicitConversionSequence::Better: 3217 // Cand1 has a better conversion sequence. 3218 return true; 3219 3220 case ImplicitConversionSequence::Worse: 3221 // Cand1 can't be better than Cand2. 3222 return false; 3223 3224 case ImplicitConversionSequence::Indistinguishable: 3225 // Do nothing 3226 break; 3227 } 3228 } 3229 3230 return false; 3231} 3232 3233/// BestViableFunction - Computes the best viable function (C++ 13.3.3) 3234/// within an overload candidate set. If overloading is successful, 3235/// the result will be OR_Success and Best will be set to point to the 3236/// best viable function within the candidate set. Otherwise, one of 3237/// several kinds of errors will be returned; see 3238/// Sema::OverloadingResult. 3239Sema::OverloadingResult 3240Sema::BestViableFunction(OverloadCandidateSet& CandidateSet, 3241 OverloadCandidateSet::iterator& Best) 3242{ 3243 // Find the best viable function. 3244 Best = CandidateSet.end(); 3245 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 3246 Cand != CandidateSet.end(); ++Cand) { 3247 if (Cand->Viable) { 3248 if (Best == CandidateSet.end() || isBetterOverloadCandidate(*Cand, *Best)) 3249 Best = Cand; 3250 } 3251 } 3252 3253 // If we didn't find any viable functions, abort. 3254 if (Best == CandidateSet.end()) 3255 return OR_No_Viable_Function; 3256 3257 // Make sure that this function is better than every other viable 3258 // function. If not, we have an ambiguity. 3259 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 3260 Cand != CandidateSet.end(); ++Cand) { 3261 if (Cand->Viable && 3262 Cand != Best && 3263 !isBetterOverloadCandidate(*Best, *Cand)) { 3264 Best = CandidateSet.end(); 3265 return OR_Ambiguous; 3266 } 3267 } 3268 3269 // Best is the best viable function. 3270 return OR_Success; 3271} 3272 3273/// PrintOverloadCandidates - When overload resolution fails, prints 3274/// diagnostic messages containing the candidates in the candidate 3275/// set. If OnlyViable is true, only viable candidates will be printed. 3276void 3277Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet, 3278 bool OnlyViable) 3279{ 3280 OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 3281 LastCand = CandidateSet.end(); 3282 for (; Cand != LastCand; ++Cand) { 3283 if (Cand->Viable || !OnlyViable) { 3284 if (Cand->Function) { 3285 // Normal function 3286 Diag(Cand->Function->getLocation(), diag::err_ovl_candidate); 3287 } else if (Cand->IsSurrogate) { 3288 // Desugar the type of the surrogate down to a function type, 3289 // retaining as many typedefs as possible while still showing 3290 // the function type (and, therefore, its parameter types). 3291 QualType FnType = Cand->Surrogate->getConversionType(); 3292 bool isReference = false; 3293 bool isPointer = false; 3294 if (const ReferenceType *FnTypeRef = FnType->getAsReferenceType()) { 3295 FnType = FnTypeRef->getPointeeType(); 3296 isReference = true; 3297 } 3298 if (const PointerType *FnTypePtr = FnType->getAsPointerType()) { 3299 FnType = FnTypePtr->getPointeeType(); 3300 isPointer = true; 3301 } 3302 // Desugar down to a function type. 3303 FnType = QualType(FnType->getAsFunctionType(), 0); 3304 // Reconstruct the pointer/reference as appropriate. 3305 if (isPointer) FnType = Context.getPointerType(FnType); 3306 if (isReference) FnType = Context.getReferenceType(FnType); 3307 3308 Diag(Cand->Surrogate->getLocation(), diag::err_ovl_surrogate_cand) 3309 << FnType; 3310 } else { 3311 // FIXME: We need to get the identifier in here 3312 // FIXME: Do we want the error message to point at the 3313 // operator? (built-ins won't have a location) 3314 QualType FnType 3315 = Context.getFunctionType(Cand->BuiltinTypes.ResultTy, 3316 Cand->BuiltinTypes.ParamTypes, 3317 Cand->Conversions.size(), 3318 false, 0); 3319 3320 Diag(SourceLocation(), diag::err_ovl_builtin_candidate) << FnType; 3321 } 3322 } 3323 } 3324} 3325 3326/// ResolveAddressOfOverloadedFunction - Try to resolve the address of 3327/// an overloaded function (C++ [over.over]), where @p From is an 3328/// expression with overloaded function type and @p ToType is the type 3329/// we're trying to resolve to. For example: 3330/// 3331/// @code 3332/// int f(double); 3333/// int f(int); 3334/// 3335/// int (*pfd)(double) = f; // selects f(double) 3336/// @endcode 3337/// 3338/// This routine returns the resulting FunctionDecl if it could be 3339/// resolved, and NULL otherwise. When @p Complain is true, this 3340/// routine will emit diagnostics if there is an error. 3341FunctionDecl * 3342Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType, 3343 bool Complain) { 3344 QualType FunctionType = ToType; 3345 if (const PointerLikeType *ToTypePtr = ToType->getAsPointerLikeType()) 3346 FunctionType = ToTypePtr->getPointeeType(); 3347 3348 // We only look at pointers or references to functions. 3349 if (!FunctionType->isFunctionType()) 3350 return 0; 3351 3352 // Find the actual overloaded function declaration. 3353 OverloadedFunctionDecl *Ovl = 0; 3354 3355 // C++ [over.over]p1: 3356 // [...] [Note: any redundant set of parentheses surrounding the 3357 // overloaded function name is ignored (5.1). ] 3358 Expr *OvlExpr = From->IgnoreParens(); 3359 3360 // C++ [over.over]p1: 3361 // [...] The overloaded function name can be preceded by the & 3362 // operator. 3363 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(OvlExpr)) { 3364 if (UnOp->getOpcode() == UnaryOperator::AddrOf) 3365 OvlExpr = UnOp->getSubExpr()->IgnoreParens(); 3366 } 3367 3368 // Try to dig out the overloaded function. 3369 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(OvlExpr)) 3370 Ovl = dyn_cast<OverloadedFunctionDecl>(DR->getDecl()); 3371 3372 // If there's no overloaded function declaration, we're done. 3373 if (!Ovl) 3374 return 0; 3375 3376 // Look through all of the overloaded functions, searching for one 3377 // whose type matches exactly. 3378 // FIXME: When templates or using declarations come along, we'll actually 3379 // have to deal with duplicates, partial ordering, etc. For now, we 3380 // can just do a simple search. 3381 FunctionType = Context.getCanonicalType(FunctionType.getUnqualifiedType()); 3382 for (OverloadedFunctionDecl::function_iterator Fun = Ovl->function_begin(); 3383 Fun != Ovl->function_end(); ++Fun) { 3384 // C++ [over.over]p3: 3385 // Non-member functions and static member functions match 3386 // targets of type “pointer-to-function”or 3387 // “reference-to-function.” 3388 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(*Fun)) 3389 if (!Method->isStatic()) 3390 continue; 3391 3392 if (FunctionType == Context.getCanonicalType((*Fun)->getType())) 3393 return *Fun; 3394 } 3395 3396 return 0; 3397} 3398 3399/// ResolveOverloadedCallFn - Given the call expression that calls Fn 3400/// (which eventually refers to the set of overloaded functions in 3401/// Ovl) and the call arguments Args/NumArgs, attempt to resolve the 3402/// function call down to a specific function. If overload resolution 3403/// succeeds, returns the function declaration produced by overload 3404/// resolution. Otherwise, emits diagnostics, deletes all of the 3405/// arguments and Fn, and returns NULL. 3406FunctionDecl *Sema::ResolveOverloadedCallFn(Expr *Fn, OverloadedFunctionDecl *Ovl, 3407 SourceLocation LParenLoc, 3408 Expr **Args, unsigned NumArgs, 3409 SourceLocation *CommaLocs, 3410 SourceLocation RParenLoc) { 3411 OverloadCandidateSet CandidateSet; 3412 AddOverloadCandidates(Ovl, Args, NumArgs, CandidateSet); 3413 OverloadCandidateSet::iterator Best; 3414 switch (BestViableFunction(CandidateSet, Best)) { 3415 case OR_Success: 3416 return Best->Function; 3417 3418 case OR_No_Viable_Function: 3419 Diag(Fn->getSourceRange().getBegin(), 3420 diag::err_ovl_no_viable_function_in_call) 3421 << Ovl->getDeclName() << (unsigned)CandidateSet.size() 3422 << Fn->getSourceRange(); 3423 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3424 break; 3425 3426 case OR_Ambiguous: 3427 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_ambiguous_call) 3428 << Ovl->getDeclName() << Fn->getSourceRange(); 3429 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3430 break; 3431 } 3432 3433 // Overload resolution failed. Destroy all of the subexpressions and 3434 // return NULL. 3435 Fn->Destroy(Context); 3436 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 3437 Args[Arg]->Destroy(Context); 3438 return 0; 3439} 3440 3441/// BuildCallToMemberFunction - Build a call to a member 3442/// function. MemExpr is the expression that refers to the member 3443/// function (and includes the object parameter), Args/NumArgs are the 3444/// arguments to the function call (not including the object 3445/// parameter). The caller needs to validate that the member 3446/// expression refers to a member function or an overloaded member 3447/// function. 3448Sema::ExprResult 3449Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, 3450 SourceLocation LParenLoc, Expr **Args, 3451 unsigned NumArgs, SourceLocation *CommaLocs, 3452 SourceLocation RParenLoc) { 3453 // Dig out the member expression. This holds both the object 3454 // argument and the member function we're referring to. 3455 MemberExpr *MemExpr = 0; 3456 if (ParenExpr *ParenE = dyn_cast<ParenExpr>(MemExprE)) 3457 MemExpr = dyn_cast<MemberExpr>(ParenE->getSubExpr()); 3458 else 3459 MemExpr = dyn_cast<MemberExpr>(MemExprE); 3460 assert(MemExpr && "Building member call without member expression"); 3461 3462 // Extract the object argument. 3463 Expr *ObjectArg = MemExpr->getBase(); 3464 if (MemExpr->isArrow()) 3465 ObjectArg = new UnaryOperator(ObjectArg, UnaryOperator::Deref, 3466 ObjectArg->getType()->getAsPointerType()->getPointeeType(), 3467 SourceLocation()); 3468 CXXMethodDecl *Method = 0; 3469 if (OverloadedFunctionDecl *Ovl 3470 = dyn_cast<OverloadedFunctionDecl>(MemExpr->getMemberDecl())) { 3471 // Add overload candidates 3472 OverloadCandidateSet CandidateSet; 3473 for (OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(), 3474 FuncEnd = Ovl->function_end(); 3475 Func != FuncEnd; ++Func) { 3476 assert(isa<CXXMethodDecl>(*Func) && "Function is not a method"); 3477 Method = cast<CXXMethodDecl>(*Func); 3478 AddMethodCandidate(Method, ObjectArg, Args, NumArgs, CandidateSet, 3479 /*SuppressUserConversions=*/false); 3480 } 3481 3482 OverloadCandidateSet::iterator Best; 3483 switch (BestViableFunction(CandidateSet, Best)) { 3484 case OR_Success: 3485 Method = cast<CXXMethodDecl>(Best->Function); 3486 break; 3487 3488 case OR_No_Viable_Function: 3489 Diag(MemExpr->getSourceRange().getBegin(), 3490 diag::err_ovl_no_viable_member_function_in_call) 3491 << Ovl->getDeclName() << (unsigned)CandidateSet.size() 3492 << MemExprE->getSourceRange(); 3493 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3494 // FIXME: Leaking incoming expressions! 3495 return true; 3496 3497 case OR_Ambiguous: 3498 Diag(MemExpr->getSourceRange().getBegin(), 3499 diag::err_ovl_ambiguous_member_call) 3500 << Ovl->getDeclName() << MemExprE->getSourceRange(); 3501 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3502 // FIXME: Leaking incoming expressions! 3503 return true; 3504 } 3505 3506 FixOverloadedFunctionReference(MemExpr, Method); 3507 } else { 3508 Method = dyn_cast<CXXMethodDecl>(MemExpr->getMemberDecl()); 3509 } 3510 3511 assert(Method && "Member call to something that isn't a method?"); 3512 llvm::OwningPtr<CXXMemberCallExpr> 3513 TheCall(new CXXMemberCallExpr(MemExpr, Args, NumArgs, 3514 Method->getResultType().getNonReferenceType(), 3515 RParenLoc)); 3516 3517 // Convert the object argument (for a non-static member function call). 3518 if (!Method->isStatic() && 3519 PerformObjectArgumentInitialization(ObjectArg, Method)) 3520 return true; 3521 MemExpr->setBase(ObjectArg); 3522 3523 // Convert the rest of the arguments 3524 const FunctionTypeProto *Proto = cast<FunctionTypeProto>(Method->getType()); 3525 if (ConvertArgumentsForCall(&*TheCall, MemExpr, Method, Proto, Args, NumArgs, 3526 RParenLoc)) 3527 return true; 3528 3529 return CheckFunctionCall(Method, TheCall.take()).release(); 3530} 3531 3532/// BuildCallToObjectOfClassType - Build a call to an object of class 3533/// type (C++ [over.call.object]), which can end up invoking an 3534/// overloaded function call operator (@c operator()) or performing a 3535/// user-defined conversion on the object argument. 3536Sema::ExprResult 3537Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object, 3538 SourceLocation LParenLoc, 3539 Expr **Args, unsigned NumArgs, 3540 SourceLocation *CommaLocs, 3541 SourceLocation RParenLoc) { 3542 assert(Object->getType()->isRecordType() && "Requires object type argument"); 3543 const RecordType *Record = Object->getType()->getAsRecordType(); 3544 3545 // C++ [over.call.object]p1: 3546 // If the primary-expression E in the function call syntax 3547 // evaluates to a class object of type “cv T”, then the set of 3548 // candidate functions includes at least the function call 3549 // operators of T. The function call operators of T are obtained by 3550 // ordinary lookup of the name operator() in the context of 3551 // (E).operator(). 3552 OverloadCandidateSet CandidateSet; 3553 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); 3554 DeclContext::lookup_const_iterator Oper, OperEnd; 3555 for (llvm::tie(Oper, OperEnd) = Record->getDecl()->lookup(OpName); 3556 Oper != OperEnd; ++Oper) 3557 AddMethodCandidate(cast<CXXMethodDecl>(*Oper), Object, Args, NumArgs, 3558 CandidateSet, /*SuppressUserConversions=*/false); 3559 3560 // C++ [over.call.object]p2: 3561 // In addition, for each conversion function declared in T of the 3562 // form 3563 // 3564 // operator conversion-type-id () cv-qualifier; 3565 // 3566 // where cv-qualifier is the same cv-qualification as, or a 3567 // greater cv-qualification than, cv, and where conversion-type-id 3568 // denotes the type "pointer to function of (P1,...,Pn) returning 3569 // R", or the type "reference to pointer to function of 3570 // (P1,...,Pn) returning R", or the type "reference to function 3571 // of (P1,...,Pn) returning R", a surrogate call function [...] 3572 // is also considered as a candidate function. Similarly, 3573 // surrogate call functions are added to the set of candidate 3574 // functions for each conversion function declared in an 3575 // accessible base class provided the function is not hidden 3576 // within T by another intervening declaration. 3577 // 3578 // FIXME: Look in base classes for more conversion operators! 3579 OverloadedFunctionDecl *Conversions 3580 = cast<CXXRecordDecl>(Record->getDecl())->getConversionFunctions(); 3581 for (OverloadedFunctionDecl::function_iterator 3582 Func = Conversions->function_begin(), 3583 FuncEnd = Conversions->function_end(); 3584 Func != FuncEnd; ++Func) { 3585 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func); 3586 3587 // Strip the reference type (if any) and then the pointer type (if 3588 // any) to get down to what might be a function type. 3589 QualType ConvType = Conv->getConversionType().getNonReferenceType(); 3590 if (const PointerType *ConvPtrType = ConvType->getAsPointerType()) 3591 ConvType = ConvPtrType->getPointeeType(); 3592 3593 if (const FunctionTypeProto *Proto = ConvType->getAsFunctionTypeProto()) 3594 AddSurrogateCandidate(Conv, Proto, Object, Args, NumArgs, CandidateSet); 3595 } 3596 3597 // Perform overload resolution. 3598 OverloadCandidateSet::iterator Best; 3599 switch (BestViableFunction(CandidateSet, Best)) { 3600 case OR_Success: 3601 // Overload resolution succeeded; we'll build the appropriate call 3602 // below. 3603 break; 3604 3605 case OR_No_Viable_Function: 3606 Diag(Object->getSourceRange().getBegin(), 3607 diag::err_ovl_no_viable_object_call) 3608 << Object->getType() << (unsigned)CandidateSet.size() 3609 << Object->getSourceRange(); 3610 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3611 break; 3612 3613 case OR_Ambiguous: 3614 Diag(Object->getSourceRange().getBegin(), 3615 diag::err_ovl_ambiguous_object_call) 3616 << Object->getType() << Object->getSourceRange(); 3617 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3618 break; 3619 } 3620 3621 if (Best == CandidateSet.end()) { 3622 // We had an error; delete all of the subexpressions and return 3623 // the error. 3624 delete Object; 3625 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3626 delete Args[ArgIdx]; 3627 return true; 3628 } 3629 3630 if (Best->Function == 0) { 3631 // Since there is no function declaration, this is one of the 3632 // surrogate candidates. Dig out the conversion function. 3633 CXXConversionDecl *Conv 3634 = cast<CXXConversionDecl>( 3635 Best->Conversions[0].UserDefined.ConversionFunction); 3636 3637 // We selected one of the surrogate functions that converts the 3638 // object parameter to a function pointer. Perform the conversion 3639 // on the object argument, then let ActOnCallExpr finish the job. 3640 // FIXME: Represent the user-defined conversion in the AST! 3641 ImpCastExprToType(Object, 3642 Conv->getConversionType().getNonReferenceType(), 3643 Conv->getConversionType()->isReferenceType()); 3644 return ActOnCallExpr(S, ExprArg(*this, Object), LParenLoc, 3645 MultiExprArg(*this, (ExprTy**)Args, NumArgs), 3646 CommaLocs, RParenLoc).release(); 3647 } 3648 3649 // We found an overloaded operator(). Build a CXXOperatorCallExpr 3650 // that calls this method, using Object for the implicit object 3651 // parameter and passing along the remaining arguments. 3652 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 3653 const FunctionTypeProto *Proto = Method->getType()->getAsFunctionTypeProto(); 3654 3655 unsigned NumArgsInProto = Proto->getNumArgs(); 3656 unsigned NumArgsToCheck = NumArgs; 3657 3658 // Build the full argument list for the method call (the 3659 // implicit object parameter is placed at the beginning of the 3660 // list). 3661 Expr **MethodArgs; 3662 if (NumArgs < NumArgsInProto) { 3663 NumArgsToCheck = NumArgsInProto; 3664 MethodArgs = new Expr*[NumArgsInProto + 1]; 3665 } else { 3666 MethodArgs = new Expr*[NumArgs + 1]; 3667 } 3668 MethodArgs[0] = Object; 3669 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3670 MethodArgs[ArgIdx + 1] = Args[ArgIdx]; 3671 3672 Expr *NewFn = new DeclRefExpr(Method, Method->getType(), 3673 SourceLocation()); 3674 UsualUnaryConversions(NewFn); 3675 3676 // Once we've built TheCall, all of the expressions are properly 3677 // owned. 3678 QualType ResultTy = Method->getResultType().getNonReferenceType(); 3679 llvm::OwningPtr<CXXOperatorCallExpr> 3680 TheCall(new CXXOperatorCallExpr(NewFn, MethodArgs, NumArgs + 1, 3681 ResultTy, RParenLoc)); 3682 delete [] MethodArgs; 3683 3684 // We may have default arguments. If so, we need to allocate more 3685 // slots in the call for them. 3686 if (NumArgs < NumArgsInProto) 3687 TheCall->setNumArgs(NumArgsInProto + 1); 3688 else if (NumArgs > NumArgsInProto) 3689 NumArgsToCheck = NumArgsInProto; 3690 3691 // Initialize the implicit object parameter. 3692 if (PerformObjectArgumentInitialization(Object, Method)) 3693 return true; 3694 TheCall->setArg(0, Object); 3695 3696 // Check the argument types. 3697 for (unsigned i = 0; i != NumArgsToCheck; i++) { 3698 Expr *Arg; 3699 if (i < NumArgs) { 3700 Arg = Args[i]; 3701 3702 // Pass the argument. 3703 QualType ProtoArgType = Proto->getArgType(i); 3704 if (PerformCopyInitialization(Arg, ProtoArgType, "passing")) 3705 return true; 3706 } else { 3707 Arg = new CXXDefaultArgExpr(Method->getParamDecl(i)); 3708 } 3709 3710 TheCall->setArg(i + 1, Arg); 3711 } 3712 3713 // If this is a variadic call, handle args passed through "...". 3714 if (Proto->isVariadic()) { 3715 // Promote the arguments (C99 6.5.2.2p7). 3716 for (unsigned i = NumArgsInProto; i != NumArgs; i++) { 3717 Expr *Arg = Args[i]; 3718 3719 DefaultVariadicArgumentPromotion(Arg, VariadicMethod); 3720 TheCall->setArg(i + 1, Arg); 3721 } 3722 } 3723 3724 return CheckFunctionCall(Method, TheCall.take()).release(); 3725} 3726 3727/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> 3728/// (if one exists), where @c Base is an expression of class type and 3729/// @c Member is the name of the member we're trying to find. 3730Action::ExprResult 3731Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc, 3732 SourceLocation MemberLoc, 3733 IdentifierInfo &Member) { 3734 assert(Base->getType()->isRecordType() && "left-hand side must have class type"); 3735 3736 // C++ [over.ref]p1: 3737 // 3738 // [...] An expression x->m is interpreted as (x.operator->())->m 3739 // for a class object x of type T if T::operator->() exists and if 3740 // the operator is selected as the best match function by the 3741 // overload resolution mechanism (13.3). 3742 // FIXME: look in base classes. 3743 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); 3744 OverloadCandidateSet CandidateSet; 3745 const RecordType *BaseRecord = Base->getType()->getAsRecordType(); 3746 3747 DeclContext::lookup_const_iterator Oper, OperEnd; 3748 for (llvm::tie(Oper, OperEnd) = BaseRecord->getDecl()->lookup(OpName); 3749 Oper != OperEnd; ++Oper) 3750 AddMethodCandidate(cast<CXXMethodDecl>(*Oper), Base, 0, 0, CandidateSet, 3751 /*SuppressUserConversions=*/false); 3752 3753 llvm::OwningPtr<Expr> BasePtr(Base); 3754 3755 // Perform overload resolution. 3756 OverloadCandidateSet::iterator Best; 3757 switch (BestViableFunction(CandidateSet, Best)) { 3758 case OR_Success: 3759 // Overload resolution succeeded; we'll build the call below. 3760 break; 3761 3762 case OR_No_Viable_Function: 3763 if (CandidateSet.empty()) 3764 Diag(OpLoc, diag::err_typecheck_member_reference_arrow) 3765 << BasePtr->getType() << BasePtr->getSourceRange(); 3766 else 3767 Diag(OpLoc, diag::err_ovl_no_viable_oper) 3768 << "operator->" << (unsigned)CandidateSet.size() 3769 << BasePtr->getSourceRange(); 3770 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3771 return true; 3772 3773 case OR_Ambiguous: 3774 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 3775 << "operator->" << BasePtr->getSourceRange(); 3776 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3777 return true; 3778 } 3779 3780 // Convert the object parameter. 3781 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 3782 if (PerformObjectArgumentInitialization(Base, Method)) 3783 return true; 3784 3785 // No concerns about early exits now. 3786 BasePtr.take(); 3787 3788 // Build the operator call. 3789 Expr *FnExpr = new DeclRefExpr(Method, Method->getType(), SourceLocation()); 3790 UsualUnaryConversions(FnExpr); 3791 Base = new CXXOperatorCallExpr(FnExpr, &Base, 1, 3792 Method->getResultType().getNonReferenceType(), 3793 OpLoc); 3794 return ActOnMemberReferenceExpr(S, ExprArg(*this, Base), OpLoc, tok::arrow, 3795 MemberLoc, Member).release(); 3796} 3797 3798/// FixOverloadedFunctionReference - E is an expression that refers to 3799/// a C++ overloaded function (possibly with some parentheses and 3800/// perhaps a '&' around it). We have resolved the overloaded function 3801/// to the function declaration Fn, so patch up the expression E to 3802/// refer (possibly indirectly) to Fn. 3803void Sema::FixOverloadedFunctionReference(Expr *E, FunctionDecl *Fn) { 3804 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 3805 FixOverloadedFunctionReference(PE->getSubExpr(), Fn); 3806 E->setType(PE->getSubExpr()->getType()); 3807 } else if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { 3808 assert(UnOp->getOpcode() == UnaryOperator::AddrOf && 3809 "Can only take the address of an overloaded function"); 3810 FixOverloadedFunctionReference(UnOp->getSubExpr(), Fn); 3811 E->setType(Context.getPointerType(E->getType())); 3812 } else if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E)) { 3813 assert(isa<OverloadedFunctionDecl>(DR->getDecl()) && 3814 "Expected overloaded function"); 3815 DR->setDecl(Fn); 3816 E->setType(Fn->getType()); 3817 } else if (MemberExpr *MemExpr = dyn_cast<MemberExpr>(E)) { 3818 MemExpr->setMemberDecl(Fn); 3819 E->setType(Fn->getType()); 3820 } else { 3821 assert(false && "Invalid reference to overloaded function"); 3822 } 3823} 3824 3825} // end namespace clang 3826